Proposed a method for System Fuzzy Control and Fault Diagnosis based on TRIZ theory. We got the method through the analysis of TRIZ matrix and 40 invention principles.In the proposed method, the different operation time parameters were compared and the Fuzzy Control and Fault Diagnosis could be realized by the change of time parameters. PLC program stored and compared the time parameters, and the program executed fuzzy control and fault diagnosis operation based on the engineering experience. Other parameters, such as flow, pressure, could be used too. The method got good response in engineering field in practice.