To improve the efficiency of obstacle avoidance path planning of collaborative robot in complex environments, improved Artificial Potential Field & Rapidly exploring Random Tree (APF-RRT) algorithm for ellipsoid obstacles. First of all, enveloped obstacle with ellipsoid bounding box,then the collision detection method was analyzed; In addition, to speed up path exploration Random point effect and random point selection mechanism were introduced to improve the RRT algorithm, then the hybrid method of improved RRT and artificial potential field was uesd for path planning; Finally, deleted redundant points on the planned path, and four-time B-spline curve was used for path smoothness, improved path quality.The simulation results showed that, in the ellipsoid obstacle environment, the algorithm can complete the obstacle avoidance path planning quickly and the planned path was shorter.