When the inspection robot runs on the overhead transmission line, self-adaptive climbing ability is an important index to estimate the robot application to real complex conditions, especially in the mountainous areas. The slipping of driving wheel usually happens when the robot climbs the lines with slopes, which would increase the abrasion of the driving wheel, reduce the efficiency of operation and waste the energy. So it is important to develop the wheels slipping identification and control method to improve the climbing ability of the inspection robot. This paper proposed a self-adaptive slipping identification and control method aiming to solve the slipping problem of the driving wheels. Firstly, the mechanism and force situation of the robot has been analyzed when the wheel slipping happens. Then we discussed the major factors to control the robot slipping and developed a dynamic model to identify the wheel slipping. Finally, we proposed a slipping identification strategy and a fuzzy control-based slipping control method. This slipping identification and control method have been tested by the experimental and practical field experiments to make the robot run in the experimental lines and the high voltage transmission lines (HVTL) in real, respectively. The performance results indicate that the proposed method is effective to improve the robot self-adaptive capacity to climb on the lines with slope and enhance the autonomous climbing and running ability of the robot.