Abstract: A type of mobile robot with self-positioning function was developed to accomplish the task of repairing large turbine blades with complex curved surface in closed on-site environment.The robot system consisted of a gapped-adhesive mobile platform, a multi-degree-of-freedom manipulator and a multi-functional operation unit.It can reliably adhere to the blade while flexibly moving on the blade surface, and complete all-position welding, air gouging and grinding tasks.The hardware platform of the self-positioning system was built using the inclinometer to adjust the pose information acquired by the inertial navigating method, and using the geometric feature of the blade surface to adjust the position information acquired by the odometry method.The experiments on the simulating blade showed that the pose error was less than 0.5° and the position error was around 35 mm, which can satisfy the self-positioning precision requirement of the blade-repairing tasks.