public class ProcessRequest : System.Web.Services.WebService
    {

       [WebMethod]
        public Customer RegisterCustomer(Customer customer)
        {
            var obj = new Customer();
            obj.Name = customer.Name +"_Return";
            obj.LastName = customer.LastName + "_Return";
            obj.AnotherAttribute = customer.AnotherAttribute + "_Return";

            return obj;
        }

        public class Customer
        {
            public string Name { get; set; }
            public string AnotherAttribute { get; set; }
            public string LastName { get; set; }
        }
}

<?php
header("Content-type:text/html;charset=utf-8");
?>
<?php
echo "<br/>-----------PHP通过传递对象参数调用asp.net服务测试--------------<br/>";
$object = new stdClass();
$object->Name = "Test";
$object->LastName = "More tests";
$object->AnotherAttribute = "Abc";
$client = new SoapClient('http://localhost:8091/ProcessRequest.asmx?WSDL');
$result = $client->RegisterCustomer(array('customer' => $object));
print_r($result);
$myObj = $result->RegisterCustomerResult;

echo "<br/>Name:";

print_r($myObj->Name); ?>

-----------PHP通过传递对象参数调用asp.net服务测试--------------
stdClass Object ( [RegisterCustomerResult] => stdClass Object ( [Name] => Test_Return [AnotherAttribute] => Abc_Return [LastName] => More tests_Return ) ) 
Name:Test_Return