Abstract: The mechanical model and dynamic equations of a manipulator, which consists of three joints and three links and operates in a horizontal plane, are established. The Reset Integrator friction model, which was developed by D. A. Haessig. Jr, is adopted to investigate the dynamic response of the manipulator by numerical simulation. The results for different parameters are compared. It is found that the effects of friction on the dynamics of the manipulator are dependent on not only the value of friction coefficient, but also the equivalent spring stiffness of joint, driving velocity and gravity.