Paper analyzed diagnosis technologies that were applied to manufacturing equipment, and researched the unidirectional mesh data structure of the fault essence. Then the integrated diagnosis method was proposed. The method was based on structure-fault tree, which has a good capability in knowledge management and maintenance. Diagnosis knowledge representation and organization model was expatiated, at same time the integrated reasoning process was accomplished. Finally, a prototype system for the CNC machine was developed that has verified the method’s correctness and feasibility.