By analyzing the types, causes and the fault feature of common fault of squirrel-cage asynchronous motor, and based on the study of the principles and methods of fault detection of electromotor, the multi-channel electric power data acquisition system is designed, which can realize the online fault detection of motor. Using AT89C52 microcontroller as the core components of the controller, and data collection use a special measurement chip CS5460. The data collected is transmitted to the upper computer by RS232 bus so as to realize the electric energy data. Sampling interpolation FFT algorithm make software compensation, and then the MCU high-speed interval of multi-channel data acquisition is realized.