Abstract: As an important component and transmission part of GIS switcher, the insulation pull rod with high reliability of mechanical and electrical performance is the key to realize the opening and closing operation of the GIS circuit breaker. There is no effective quality inspection method for insulation pull rods currently. Thus, the defect detection method combined with the industrial CT for GIS insulation pull rod is proposed and experiments are carried out. The experimental results show that the avail able method based on industrial CT can determine the nature, location and size of the defect accurately compared with the traditional non-destructive testing methods. More importantly, the method can detect the defects timely and accurately in order to ensure the quality of the equipment before its putting into operation. The research provides a new idea for the defect detection of GIS insulation pull rods, which is of great significance for improving the quality of insulation pull rods and ensuring the stable operation of GIS switcher.