Turbine generator is one of the most critical devices in nuclear power plant. Ensuring its safe and stable operation through effective maintenance measures is a necessary condition to ensure the safety and benefit of nuclear power plant. Currently, the detection of the state of generator body by robot instead of generator rotor checking has been widely applied. To adapt to the detection in the air gap of stators and rotors of different generators, weight reduction should be considered in the design of robot body, and aviation grade aluminum alloy and other materials can be used; to ensure that the robot can walk in the generator bore with different sizes and radians, the mechanical structure with adjustable width and angle should be considered in the design; the design of robot system should include image recognition system, slot wedge tightness detection system, automatic deviation adjustment system, and capability of remote control through cables. Compared with other existing robots, the robot designed in this paper has more comprehensive functions and can better cope with the actual working conditions of different generators without rotor drawing.