According to the theory of passivity, the force control on the robot system is studied from a relatively new perspective. In general, a strictly passive dynamic system has a good dynamic characteristics and robustness. Therefore, a passive approach to force control is presented in the force controller design. In view of the uncertainty and environmental impacts in robot modeling, the paper adds a compensation term to compensate for model uncertainty in force control loop. The simulation results show that this control program enhances the dynamic performance and robustness of the system.