The electric spindle is the executive body of the numerical control products, because of its highly integrated structure, the industry has not yet summarized a scientific and efficient method of fault diagnosis, resulting in its fault diagnosis thinking mode and long processing cycle, the normal processing of the product is seriously affected. Taking the fault diagnosis process of Fisher Electric spindle used in a six-axis five-linkage bridge CNC machine tool as an example, this paper studies and summarizes the process of distinguishing and analyzing the typical fault causes by using the Datsan method, this paper presents a method for rapid diagnosis of machine tool spindle faults, which can be used for reference by engineers and technicians in dealing with similar equipment faults.