This paper explores design and control methods of a surgical robot for total hip replacement surgery which can be easily maneuvered by a surgeon Like an advanced surgical tool. The 3-DOF in-parallel surgical robot is fixed directly onto patient's femur by the bone clamp during surgery. With the master/slave combined surgical robot, the surgeon can directly control the motion of the surgical robot with surgeon's experience and judgment during operation. For the easiness of operation, the master/slave combined robot is controlled using admittance control paradigm. And for the precise operation, the robot motion is restricted at the surgical boundary using virtual hard wall display.