A wall climbing robot for penstock maintenance was introduced, and its kinematic characteristics were analyzed. The mechanical structure and control system of the climbing robot were introduced, then the kinematics model of the welding robot was established by using D-H parameter method, and the forward and inverse kinematics equations were constructed. Then, the robot forward and inverse kinematics equations were solved by using Robot Toolbox, the 3D simulation image of the robot was displayed online.The displacement, velocity and acceleration curves of each joint were analyzed, and the trajectory of the robot end was planned, which verified the rationality of the robot structure.