后台： 

public string UploadImage()
        {
            LayuiEdit edit = new LayuiEdit();
            var file = Request.Files[0];
            string filepath = "";
            var name = string.Empty;
            name = Guid.NewGuid().ToString("N") + DateTime.Now.ToString("yyyyMMddHHmmssfff") + Path.GetExtension(file.FileName);
            try
            {
                //文件不为空
                if (file != null)
                {
                    //创建年月文件夹，如201605
                    string fileFolder = DateTime.Now.ToString("yyyyMM");
                    //拼接保存时根路径，比如：D:Work/MVCTest/Uploads/201605
                    string pathForSaving = Server.MapPath("/Uploads/Image/") + fileFolder;
                    //判断文件夹是否存在，否则创建文件夹
                    if (Tool.CreateFolderIsNeeded(pathForSaving))
                    {
                        //判断上传文件的大小
                        if (file.ContentLength > 0)
                        {
                            //重新组合成一个存放路径，根路径+文件名称
                            filepath = Path.Combine(pathForSaving, name);
                            file.SaveAs(filepath);

                        }
                    }
                    //返回成功提示页面

                }
                //FaceModel faceModel = new FaceModel();
                //faceModel.api_key = "EScZJfELRTweCi-zWxyJpU6WHDXLBI_I";
                //faceModel.api_secret = "sj-N1FPF9garCXa50c_pirPRTrnm9vXd";
                //faceModel.image_file = filepath;
                edit.code = 0;
                data data = new data();

                //string baseImgUrl = filepath;
                string path = HttpContext.Request.Url.Authority;
                filepath = filepath.Replace("Uploads", "@");
                filepath = "/Uploads" + filepath.Split('@')[1];
                data.src = "http://" + path + filepath;
                edit.data = new data();
                edit.data = data;

                //var faceResult = FaceApi(faceModel);
                return JsonConvert.SerializeObject(edit);

            }
            catch (Exception e)
            {
                edit.code = 1;
                edit.msg = e.Message;
                data data = new data();
                edit.data = new data();
                edit.data = data;
                return JsonConvert.SerializeObject(edit);
            }
        }

前台 

var fileObj = document.getElementById(idFile).files[0];
$.ajax({
			url: "路径",
			data: {后台接收参数名:fileObj},
			type: "Post",
			dataType: "json",
			async: true,
			cache: false, //上传文件无需缓存
			processData: false, //用于对data参数进行序列化处理 这里必须false
			contentType: false, //必须
			beforeSend: function() {
				//上传之前调用的方法
			},
			success: function(result) {
				//成功
			},
			error: function() {
				//失败
				return;
			}
		})