Electromechanical coupling dynamic model of nonlinear joint with clearance was established in order to study the influence of joint clearance on vibration characteristics of industrial robot. By numerical analysis on stability of the system clearance, the torsional vibration characteristics simulation study of the joint’s key components was made. The clearance test bench was constructed to make clearance test for a single joint swing arm. A clearance compensation strategy based on torque observer was proposed on the basis of the collected current parameters. The accuracy of the joint model with clearance was verified via results of clearance test and simulation research of resonance frequency domain response of joint system. According to the test results of current signal before and after compensations, the compensation strategy can be used to improve stability of joint system.