Abstract: This paper is concerned with the hierachical tree structure of geometry model of robot, on whichthe high level is robot tree and the lower level is link tree whose node represents the primitive body. The hidden lines and faces elimination for robot graphic processing can then be performed on three different levels or-derly:primitive body──→link─→robot. Hidden removal for single primitive body is implemented by determining the priority of all faces of it; the min/max box and max-bounding contour of each primitive areused to judge the priority between multi-primitive (link); and only links are sorted for hidden removal ofrobot.The time for hidden removal computation is thus reduced greatly.The above algorithms have beenused in the robot graphic simulation.