In view of the problem of sensor fault in the multi-motor synchronous control system, the similarity matrix which characterizing the consistency of different sensors output is designed, which is enlightened by the concept of the coupling matrix of complex network synchronous output based on the information and structural redundancy in synchronous control. The fault sensor is detected, located and estimated by judging the related elements and eigenvalues in the similarity matrix. And the fault sensors can also be isolated and the system is achieved fault-tolerance by improving the weighted mean feedback mechanism. The innovation of the method is to make full use of the advantages of the convenience online data acquisition in the data driven method and the characteristics of the mechanism based on the model method, realizes the integration of the model and the data method, and avoids complex theoretical derivation. It is also applicable to multiple faults situations and has the characteristics of simple algorithm, high execution efficiency and easy engineering implementation. There is no need to change the original topology of the system. Simulation experiments verifies the effectiveness of this method.