This paper presents a method for model based bilateral control of master-slave teleoperation with time delay between master and slave arms, where the system supports cooperative action between manual and automatic modes. In the proposed system, a real time simulator model of the slave arm and a graphic display, visualizing the real and simulated motions of the slave arm, are provided to assist the operator. Based on signals from the simulator model, human operators can manipulate the master arm to move the slave arm without confusion of time delay. As long as a priori information in the computer is accurate for recognizing the working environment, the computer operates master-slave arm by using a priori knowledge. When it is necessary for human operators to adjust the motion of the slave arm, human operators can intervene in the computer operation to reduce the speed of the slave arm and change the course of the motion by moving the master arm and grasping the grid of the master arm. In this method, the fuzzy rules are applied to determine the manipulated force given to the bilateral control system so that the skilled technique of a human operator can be incorporated into the computer operation. In accordance with this manipulated force, master and slave arms are controlled by sliding mode control method respectively. Through some actual trials in a one-degree of freedom arm, this proposed method is proven to be practical in the operation of a master-slave arm, even though there were time delay between master and slave arms and the working environment were changed.