Abstract: To solve the problem that common method of fault diagnosis of motor in frequency-conversion speed-regulation system is difficult to judge fault type,the paper proposed a diagnosis method for broken-bar fault of motor based on multi-sensor information fusion.The method extracts characteristics information of broken-bar fault of motor by wavelet packet analysis,then uses D-S evidence theory to fuse and calculate characteristic information of fault,so as to identify fault.The experiment of diagnosis test showed that the method improves precision of fault diagnosis of motor and can meet with the require of real-time diagnosis.