Abstract: The "HVCR II",an articulated hot-line cleaning robot,is a kind of tele-operated robot.It is designed to clean the insulators of high voltage equipments in 330kV transformer substations.In this paper,some studies about the design of insulation and safety are presented,including insulating structure,insulating operating mode,control system,leakage current realtime measuring and alarming system.The power frequency voltage withstand test and the simulated brushing test show that the robot has great insulating ability and good application prospects.