Abstract: To avoid various sudden accidents and diagnose various faults timely and accurately during pump operation,an on-line condition monitoring and fault diagnosis system for pump is established based on CAN bus and fuzzy theory in the paper.In this system,warning function of comparatively threshold value is added using dynamic data exchange technology between configuration and Visual Basic(VB) application program.At the same time,a fault diagnosis expert system is established using mixed programming technique based on COM component between VB and MATLAB according to the fuzzy relationship between faults and symptoms during pump operation.Result of the system running shows that the system can real-time alarm when the operation conditions of pumps are abnormal.The system has good reliable performance,and it significantly enhances the level of safety management for pumps.