Abstract: In the treatment process of proton radiation therapy, the patient needs to be positioned and immobilized and then posed to the treatment position. In this study the patient was mainly posed by the 6R robotic treatment couch as the patient support system (PSS). In this study, a simplified three-dimensional model of the treatment room was established based on the relative motion in the treatment room, the forward and reverse kinematics of the 6R robotic treatment couch were analyzed using the improved D-H representation, a collision interference model was established from the actual treatment process, and the motion path of the treatment couch was planned and simulated using the improved artificial potential field method in MATLAB for obstacle avoidance. The results show that the robotic treatment couch can smoothly avoid obstacles to reach the target point, which meets the posing requirements of proton therapy.