This research is about the multi-axis combined movement posture adjustment mode of the mechanism. It can lay a theoretical foundation for the research and the optimization of process of posture adjustment mechanism. Taking the 6-DOF parallel posture adjustment robot as the research object, the kinematic model of the mechanism is established. We established a simple, high-efficiency, low-energy multi-axis combined movement posture adjustment mode for the drive of the parallel mechanism. The obstacle collision detection model is constructed, and the RRT algorithm is used to plan the motion path of the cabin docking point. We use the smoothing method to optimize the generated path, interpolate the path by using B-spline curve and obtain a smooth and continuous motion trajectory curve. Through the genetic algorithm, under the condition of satisfying the kinematic constraints, we obtained the motion trajectory of the docking point with the optimal performance index. Finally, we carried out the kinematic simulation of the docking assembly motion of the parallel posture adjustment mechanism. A reasonable multi-axis combined movement posture adjustment mode is assigned, which verifies that the posture adjustment mode and trajectory planning method in this paper are feasible.