For the offline detection of composite insulators,highpressure compression tests are used.The insulation level of insulators is rarely considered,and the detection work is mostly done by manual.A multistation automatic hydrophobic detection system for the compound insulator was designed with PLC and industrial robot as the core.The system consisted of a host computer,an industrial robot and a detector.In order to achieve the multistation detection target,an industrial robot end effector capable of clamping four composite insulators at the same time was designed.Meanwhile,the hydrophobic image of the composite insulator was extracted by the mutual matching of the disc type indexing movement device at the bottom of the detector and the twoaxis motion platform for the top mounted camera.Using the designed system,full automation and standardization operation is realized,it replaces the manual work in highpressure environment,so the safety,effectiveness and efficiency of the detection are improved.It has high promotion and application value.