To reduce the influence of operation state and external environmental factors on the output of the wind turbine, the wind turbine output correlation information is used to determine the operating state of the wind turbine. The reliability of discriminating unhealthy state or fault state of the unit is improved without increasing the sensor and the measuring point. The correlation analysis and fuzzy fault Petri nets are combined to determine the operating performance of the wind turbine and diagnose the fault. The validity of the method is demonstrated by the calculation results of the wind field data. This work is supported by Natural Science Foundation of Shanghai (No. 14ZR1400700).