In order to ensure the security of power transmission, the cleaning of polluted insulators and the inspecting of zero value insulators are routine works for the maintenance of high voltage transmission line. According to present work mode, which needs people to climb the tower, an insulator cleaning and inspection robot for high voltage transmission line was developed. The robot was carried with cleaning and inspection mechanism, which could realize the live work while climbing along the insulator string automatically. By introducing the mechanical structure of the robot in detail, its working principle was discussed. Finally, theoretical calculation and dynamic simulation by Adams were made to determine the driving force of main mechanism, and proper motors were chosen. The robot is simple in structure and convenient in operation, which forms the foundation of real prototype in the future.