Abstract：Intelligent substation uses Ethernet to transmit sampling values, binary input and parameter configuration information. Network communication performance directly affects the stability and reliability of the protection device. In the process of on-site debugging and on-site maintenance of intelligent substation, network communication failure usually lacks effective means of testing and fault location method. This paper first introduces the test mechanism of network communication in intelligent substation. Then, typical failure modes of network communication in intelligent substation are analyzed. Finally, an implementation scheme based on large-scale field programmable gate array technology is proposed for its network data flow characteristics. The test results show that the method meets the basic requirements of network communication test in intelligent substation and effectively improves the op-eration and maintenance capacity of the network system in intelligent substation.