Abstract: The paper introduced types and causes of common electrical and mechanical faults of motor, and described application of signal processing methods and intelligent diagnosis methods in fault diagnosis of motor. The signal processing methods include short-time Fourier transform, wavelet transform, wavelet packet transform and empirical mode decomposition. The intelligent diagnosis methods include expert system, fuzzy theory, support vector machine and neural network. It also pointed out development trend of fault diagnosis technologies of motor is combination of multiple diagnosis methods and information fusion method.