This paper deals with the universal serial manipulator on the inverse kinematics problem of plane type,the fast working space solution method,and the obstacle avoidance path planning method. With the vector projection as the main constraint condition of the target,it proposes a general form of the inverse kinematics solution which does not depend on the robot configuration of freedom degree. By identifying the target vector direction maximum and minimum workspace boundary and determining the destination vector by thick search on the workspace boundary method,an expressing method of the polar coordinate form of work space is then introduced. Finally,according to the form of plane trajectory planning for obstacle avoidance problem,the method of solving the inverse kinematics solution of the concave and convex forms of the safe obstacle avoidance area is improved. The simulation results verify that the proposed method has feasibility and generality. This paper deals with the universal serial manipulator on the inverse kinematics problem of plane type, the fast working space solution method, and the obstacle avoidance path planning method. With the vector projection as the main constraint condition of the target, it proposes a general form of the inverse kinematics solution does not depend on the robot configuration of freedom degree. of work space is then introduced. Finally, according to the form of plane trajectory planning for obstacle avoidance problem, the method of solving the inverse kinematics solution of the concave and convex forms of the safe obstacle avoidance area is improved. The simulation results verify that the proposed method has feasibility and generality.