In the long-term use of insulation tools for live working

minor defects may exist inside the insulating tool

and thus affect the performance of the tool. The use of ultrasonic testing technology can effectively diagnose the internal defects of the material

and ensure the safety of workers. Based on the structural characteristics of the solid rod and the hollow tube used in the insulation tool

the defect echos of the double probe solid rod and the single probe hollow tube were simulated by the COMSOL software. At the same time

the ultrasonic detection test of the insulated pipe with artificial defects was carried out. The corresponding ultrasonic detection method for live working insulation tool was proposed.The simulation and experimental results show that the ultrasonic detection of insulating solid rods can be performed by using two narrow pulse width probes plus double crystal face wedges

and the time and amplitude of defect echoes reflect the relative position; for insulation hollow ultrasonic testing

a narrow pulse broadband probe with single crystal arc wedge is used for detection

defect echo is located between the outer wall and wall echo. This method has some reference significance for the internal defect detection of insulating materials with other structures.