Introduced the basic principle and structure of the grid computing technology,as well as the application combined with the fault diagnosis expert systems.Put forward that use grid node to construct integrated fault diagnosis system based on object model,experience rule,neural network model and practice,so that the aptitude and efficiency of the diagnosis system is improved.Researched on the method of applying the grid architecture in fault diagnosis based on OGSA.It also puts forward the method of fault diagnosis in LAN.Server is made up of grid nodes,which are used for spectrum diagnosis and data tendency diagnosis.Using web Service program,can realize accessing and grid calculating between clients and server.Besides,presented the system control flow.