需要配合ICSharpCode.SharpZipLib.dll 使用
源码如下：

//-------------------------------------------------------------------------------------
// All Rights Reserved , Copyright (C) 2016 , ZTO , Ltd .
//-------------------------------------------------------------------------------------using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;namespace ZTO.PicTest.Utilities
{using ICSharpCode.SharpZipLib.Checksums;using ICSharpCode.SharpZipLib.Zip;/// <summary>/// Zip压缩帮助类////// 修改纪录//////     2015-09-16  版本：1.0 YangHengLian 创建主键，注意命名空间的排序。///     2016-5-7 YangHengLian增加了可以支持多个文件或者多个文件夹打包成一个zip文件/// /// 版本：1.0////// <author>///        <name>YangHengLian</name>///        <date>2015-09-16</date>/// </author>/// </summary>public class ZipHelper{/// <summary>/// 压缩文件夹/// </summary>/// <param name="dirToZip"></param>/// <param name="zipedFileName"></param>/// <param name="compressionLevel">压缩率0（无压缩）9（压缩率最高）</param>public void ZipDir(string dirToZip, string zipedFileName, int compressionLevel = 9){if (Path.GetExtension(zipedFileName) != ".zip"){zipedFileName = zipedFileName + ".zip";}using (var zipoutputstream = new ZipOutputStream(File.Create(zipedFileName))){zipoutputstream.SetLevel(compressionLevel);Crc32 crc = new Crc32();Hashtable fileList = GetAllFies(dirToZip);foreach (DictionaryEntry item in fileList){FileStream fs = new FileStream(item.Key.ToString(), FileMode.Open, FileAccess.Read, FileShare.ReadWrite);byte[] buffer = new byte[fs.Length];fs.Read(buffer, 0, buffer.Length);// ZipEntry entry = new ZipEntry(item.Key.ToString().Substring(dirToZip.Length + 1));ZipEntry entry = new ZipEntry(Path.GetFileName(item.Key.ToString())){DateTime = (DateTime)item.Value,Size = fs.Length};fs.Close();crc.Reset();crc.Update(buffer);entry.Crc = crc.Value;zipoutputstream.PutNextEntry(entry);zipoutputstream.Write(buffer, 0, buffer.Length);}}}/// <summary>  /// 获取所有文件  /// </summary>  /// <returns></returns>  public Hashtable GetAllFies(string dir){Hashtable filesList = new Hashtable();DirectoryInfo fileDire = new DirectoryInfo(dir);if (!fileDire.Exists){throw new FileNotFoundException("目录:" + fileDire.FullName + "没有找到!");}GetAllDirFiles(fileDire, filesList);GetAllDirsFiles(fileDire.GetDirectories(), filesList);return filesList;}/// <summary>  /// 获取一个文件夹下的所有文件夹里的文件  /// </summary>  /// <param name="dirs"></param>  /// <param name="filesList"></param>  public void GetAllDirsFiles(IEnumerable<DirectoryInfo> dirs, Hashtable filesList){foreach (DirectoryInfo dir in dirs){foreach (FileInfo file in dir.GetFiles("*.*")){filesList.Add(file.FullName, file.LastWriteTime);}GetAllDirsFiles(dir.GetDirectories(), filesList);}}/// <summary>  /// 获取一个文件夹下的文件  /// </summary>  /// <param name="dir">目录名称</param>/// <param name="filesList">文件列表HastTable</param>  public static void GetAllDirFiles(DirectoryInfo dir, Hashtable filesList){foreach (FileInfo file in dir.GetFiles("*.*")){filesList.Add(file.FullName, file.LastWriteTime);}}/// <summary>  /// 功能：解压zip格式的文件。  /// </summary>  /// <param name="zipFilePath">压缩文件路径</param>  /// <param name="unZipDir">解压文件存放路径,为空时默认与压缩文件同一级目录下，跟压缩文件同名的文件夹</param>  /// <returns>解压是否成功</returns>  public void UnZip(string zipFilePath, string unZipDir){if (zipFilePath == string.Empty){throw new Exception("压缩文件不能为空！");}if (!File.Exists(zipFilePath)){throw new FileNotFoundException("压缩文件不存在！");}//解压文件夹为空时默认与压缩文件同一级目录下，跟压缩文件同名的文件夹  if (unZipDir == string.Empty)unZipDir = zipFilePath.Replace(Path.GetFileName(zipFilePath), Path.GetFileNameWithoutExtension(zipFilePath));if (!unZipDir.EndsWith("/"))unZipDir += "/";if (!Directory.Exists(unZipDir))Directory.CreateDirectory(unZipDir);using (var s = new ZipInputStream(File.OpenRead(zipFilePath))){ZipEntry theEntry;while ((theEntry = s.GetNextEntry()) != null){string directoryName = Path.GetDirectoryName(theEntry.Name);string fileName = Path.GetFileName(theEntry.Name);if (!string.IsNullOrEmpty(directoryName)){Directory.CreateDirectory(unZipDir + directoryName);}if (directoryName != null && !directoryName.EndsWith("/")){}if (fileName != String.Empty){using (FileStream streamWriter = File.Create(unZipDir + theEntry.Name)){int size;byte[] data = new byte[2048];while (true){size = s.Read(data, 0, data.Length);if (size > 0){streamWriter.Write(data, 0, size);}else{break;}}}}}}}/// <summary>/// 压缩单个文件/// </summary>/// <param name="filePath">被压缩的文件名称(包含文件路径)，文件的全路径</param>/// <param name="zipedFileName">压缩后的文件名称(包含文件路径)，保存的文件名称</param>/// <param name="compressionLevel">压缩率0（无压缩）到 9（压缩率最高）</param>public void ZipFile(string filePath, string zipedFileName, int compressionLevel = 9){// 如果文件没有找到，则报错 if (!File.Exists(filePath)){throw new FileNotFoundException("文件：" + filePath + "没有找到！");}// 如果压缩后名字为空就默认使用源文件名称作为压缩文件名称if (string.IsNullOrEmpty(zipedFileName)){string oldValue = Path.GetFileName(filePath);if (oldValue != null){zipedFileName = filePath.Replace(oldValue, "") + Path.GetFileNameWithoutExtension(filePath) + ".zip";}}// 如果压缩后的文件名称后缀名不是zip，就是加上zip，防止是一个乱码文件if (Path.GetExtension(zipedFileName) != ".zip"){zipedFileName = zipedFileName + ".zip";}// 如果指定位置目录不存在，创建该目录  C:\Users\yhl\Desktop\大汉三通string zipedDir = zipedFileName.Substring(0, zipedFileName.LastIndexOf("\\", StringComparison.Ordinal));if (!Directory.Exists(zipedDir)){Directory.CreateDirectory(zipedDir);}// 被压缩文件名称string filename = filePath.Substring(filePath.LastIndexOf("\\", StringComparison.Ordinal) + 1);var streamToZip = new FileStream(filePath, FileMode.Open, FileAccess.Read);var zipFile = File.Create(zipedFileName);var zipStream = new ZipOutputStream(zipFile);var zipEntry = new ZipEntry(filename);zipStream.PutNextEntry(zipEntry);zipStream.SetLevel(compressionLevel);var buffer = new byte[2048];Int32 size = streamToZip.Read(buffer, 0, buffer.Length);zipStream.Write(buffer, 0, size);try{while (size < streamToZip.Length){int sizeRead = streamToZip.Read(buffer, 0, buffer.Length);zipStream.Write(buffer, 0, sizeRead);size += sizeRead;}}finally{zipStream.Finish();zipStream.Close();streamToZip.Close();}}/// <summary> /// 压缩单个文件 /// </summary> /// <param name="fileToZip">要进行压缩的文件名，全路径</param> /// <param name="zipedFile">压缩后生成的压缩文件名,全路径</param> public void ZipFile(string fileToZip, string zipedFile){// 如果文件没有找到，则报错 if (!File.Exists(fileToZip)){throw new FileNotFoundException("指定要压缩的文件: " + fileToZip + " 不存在!");}using (FileStream fileStream = File.OpenRead(fileToZip)){byte[] buffer = new byte[fileStream.Length];fileStream.Read(buffer, 0, buffer.Length);fileStream.Close();using (FileStream zipFile = File.Create(zipedFile)){using (ZipOutputStream zipOutputStream = new ZipOutputStream(zipFile)){// string fileName = fileToZip.Substring(fileToZip.LastIndexOf("\\") + 1);string fileName = Path.GetFileName(fileToZip);var zipEntry = new ZipEntry(fileName){DateTime = DateTime.Now,IsUnicodeText = true};zipOutputStream.PutNextEntry(zipEntry);zipOutputStream.SetLevel(5);zipOutputStream.Write(buffer, 0, buffer.Length);zipOutputStream.Finish();zipOutputStream.Close();}}}}/// <summary>/// 压缩多个目录或文件/// </summary>/// <param name="folderOrFileList">待压缩的文件夹或者文件，全路径格式,是一个集合</param>/// <param name="zipedFile">压缩后的文件名，全路径格式</param>/// <param name="password">压宿密码</param>/// <returns></returns>public bool ZipManyFilesOrDictorys(IEnumerable<string> folderOrFileList, string zipedFile, string password){bool res = true;using (var s = new ZipOutputStream(File.Create(zipedFile))){s.SetLevel(6);if (!string.IsNullOrEmpty(password)){s.Password = password;}foreach (string fileOrDir in folderOrFileList){//是文件夹if (Directory.Exists(fileOrDir)){Debug.Log("ZipManyFilesOrDictorys:" + fileOrDir);res = ZipFileDictory(fileOrDir, s, "");}else{//文件res = ZipFileWithStream(fileOrDir, s);}}s.Finish();s.Close();return res;}}/// <summary>/// 带压缩流压缩单个文件/// </summary>/// <param name="fileToZip">要进行压缩的文件名</param>/// <param name="zipStream"></param>/// <returns></returns>private bool ZipFileWithStream(string fileToZip, ZipOutputStream zipStream){//如果文件没有找到，则报错if (!File.Exists(fileToZip)){throw new FileNotFoundException("指定要压缩的文件: " + fileToZip + " 不存在!");}//FileStream fs = null;FileStream zipFile = null;ZipEntry zipEntry = null;bool res = true;try{zipFile = File.OpenRead(fileToZip);byte[] buffer = new byte[zipFile.Length];zipFile.Read(buffer, 0, buffer.Length);zipFile.Close();zipEntry = new ZipEntry(Path.GetFileName(fileToZip));zipStream.PutNextEntry(zipEntry);zipStream.Write(buffer, 0, buffer.Length);}catch{res = false;}finally{if (zipEntry != null){}if (zipFile != null){zipFile.Close();}GC.Collect();GC.Collect(1);}return res;}/// <summary>/// 递归压缩文件夹方法/// </summary>/// <param name="folderToZip"></param>/// <param name="s"></param>/// <param name="parentFolderName"></param>private bool ZipFileDictory(string folderToZip, ZipOutputStream s, string parentFolderName){ZipConstants.DefaultCodePage = 0;bool res = true;ZipEntry entry = null;FileStream fs = null;Crc32 crc = new Crc32();try{//创建当前文件夹entry = new ZipEntry(Path.Combine(parentFolderName, Path.GetFileName(folderToZip) + "/")); //加上 “/” 才会当成是文件夹创建s.PutNextEntry(entry);s.Flush();//先压缩文件，再递归压缩文件夹var filenames = Directory.GetFiles(folderToZip);foreach (string file in filenames){//打开压缩文件fs = File.OpenRead(file);byte[] buffer = new byte[fs.Length];fs.Read(buffer, 0, buffer.Length);entry = new ZipEntry(Path.Combine(parentFolderName, Path.GetFileName(folderToZip) + "/" + Path.GetFileName(file)));entry.DateTime = DateTime.Now;entry.Size = fs.Length;fs.Close();crc.Reset();crc.Update(buffer);entry.Crc = crc.Value;s.PutNextEntry(entry);s.Write(buffer, 0, buffer.Length);}}catch(Exception ex){Debug.Log("ZipFileDictory catch:" + ex.Message);res = false;}finally{if (fs != null){fs.Close();}if (entry != null){}GC.Collect();GC.Collect(1);}var folders = Directory.GetDirectories(folderToZip);foreach (string folder in folders){if (!ZipFileDictory(folder, s, Path.Combine(parentFolderName, Path.GetFileName(folderToZip)))){return false;}}return res;}}
}

示例：

    /// <summary>/// 压缩文件/// </summary>/// <param name="dirToZip"></param>目标文件夹全路径/// <param name="zipedFileName"></param>输出压缩包全路径void OnZipToDir(string dirToZip, string zipedFileName){ZipHelper mZip = new ZipHelper();var dir = new string[1]{dirToZip};mZip.ZipManyFilesOrDictorys(dir, zipedFileName,null);}