WebMethod返回JSON，但是$ .ajax（）回调中的响应obj只是一个字符串

您不应该手动序列化返回值。ASP.NET将为您做到这一点。尝试这样的事情：

[WebMethod]public static Person GetPersonInfo(string pFirstName, string pLastName){  // Assuming you have a server-side Person class.  Person p = new Person();  p.FirstName = "Pseudo" + pFirstName;  p.LastName = "Tally-" + pLastName;  p.Address = "5035 Macleay Rd SE";  p.City = "Salem";  p.State = "Oregon";  p.ZipCode = "97317";  // ASP.NET will automatically JSON serialize this, if you call it with  //  the correct client-side form (which you appear to be doing).  return p;}

如果您需要返回更动态的内容（例如您的示例似乎正在做的事情），则可以使用匿名类型：

[WebMethod]public static object GetPersonInfo(string pFirstName, string pLastName){  // ASP.NET will automatically JSON serialize this as well.  return new {    FirstName = "Pseudo" + pFirstName,    LastName = "Tally-" + pLastName,    Address = "5035 Macleay Rd SE",    City = "Salem",    State = "Oregon",    ZipCode = "97317"  }}