When formatting message using Text Encoding, the data transmission will increase between the client and service channel capacity. With the increment of the file length, throughput will increase linearly and its performance will be greatly reduced. As a new generation development architecture of network transmission, WCF (Windows Communication Foundation) has extremely powerful productivity in building the service-oriented application . This paper is to be modeled on this structure. The message layer constructs SOAP (Simple Object Access Protocol) package using MTOM (Message Transmission Optimization Mechanism) and the transport layer achieve streamming mode. The use of asynchronous calls can improve applications’ performance of response. This program can significantly improve file stream transmission performance.