Abstract: On the basis of the reset integrator model, a stochastic friction model is established. A quantitative mean ratio v for the effect of friction on the motion of rigid body system is introduced. With the manipulator, which consists of three joints and three links and operates in a horizontal plane, the mean ratio v is verified and used for the evaluation of the friction effect in several different parameters by simulation. The relationship between the friction effect on the motion and the parameters, including driving velocity, the kinetic friction coefficient, the friction drop ratio between the static and kinetic friction coefficients, and the joint equivalent spring stiffness, is investigated quantitatively.