$.ajax({
            type: "POST",
            url: "/FileSys/GetFile/ZipDownload",
            data: postData,
            success: function (data) {
                alert(data.Result);
            },
            dataType: "json",
            traditional: true
        });

 [HttpPost]
        public FileResult ZipDownload(List<String> values)
        {
            List<String> lstFullFilePath = new List<String>();
            WorkFiles wf = new WorkFiles();
            foreach (var path in values)
            {
                lstFullFilePath.Add(wf.GenFullPath("\\" + path));
            }

            string GeneralDirectory = "/Documents/";

            string xDirArchive = wf.GenFullPath(GeneralDirectory + "Archive");
            if (!Directory.Exists(xDirArchive)) { Directory.CreateDirectory(xDirArchive); }

            using (ZipFile zip = new ZipFile())
            {
                zip.AlternateEncoding = Encoding.UTF8;
                zip.ProvisionalAlternateEncoding = Encoding.GetEncoding(Console.OutputEncoding.CodePage);
                zip.AlternateEncodingUsage = ZipOption.AsNecessary;

                foreach (var data in lstFullFilePath)
                { zip.AddFile(data, "files"); }

                string filepath = xDirArchive + "\\MyZipFiles.zip";
                zip.Save(filepath);
            }

            string file_path = Server.MapPath("~/Documents/Archive/MyZipFiles.zip"); 
            string file_type = "application/zip"; 
            string file_name = "MyZipFiles.zip";

            return File(file_path, file_type, file_name);

        }

$.ajax({
            type: "POST",
            url: "/FileSys/GetFile/ZipDownload",
            data: postData,
            success: function (data) {
                alert(data.Result);
            },
            dataType: "json",
            traditional: true
        });