This paper introduces the network communication fault location technique in smart substation based on comprehensive information judgment. This technique complies with the IEC61850 standard quality requirements of substation automation system topology, function layer, logical interface, basic model specification and information interaction model specification of ACSI model, and public data attribute type. According to the network technique applications, such as VLAN and Subnet, it can make real-time and precise configuration management and process management for network status, link architecture, network interface position and interface information on station level and process level of smart substation. In this case, it is possible to pinpoint and quickly find communication faults in smart substation. This technique has been tested in 110 kV smart substation. The test results indicate that, by using this technique, communication faults in smart substation can be pinpointed and quickly found and security risk can be assessed efficiently.