[Objective] To enhance the performance stability of robot joint motors in high-radiation environments, a design and prototype development are carried out for radiation-resistant robot joint motors to meet the long-term operation and maintenance requirements of nuclear industrial robots in high-radiation conditions. [Methods] Firstly, according to the basic performance parameters required for the joint motor, simulation was carried out by finite element method to get the ideal design value. Then, the main components of the joint motor were analyzed, and it was determined that the metal materials were less affected by nuclear radiation, while non-metallic materials were the weak links. Through radiation experimental verification of paint-coated wire, heat-shrinkable tube, adhesive material, lubricating grease, outgoing line, etc., the radiation-resistant performance limits of the materials used in the motor were analyzed. Finally, the appropriate materials were selected for the physical verification of the robot joint motor, so that the joint motor could withstand the γ-ray radiation level of 5 MGy. [Results] Through the designed and analysised of the joint motor, the rated torque of the motor was more than 1.5 N·m, and the rated speed of 240 r/min met the use requirements. The joint motor remained in a controlled state after 5 MGy γ-ray radiation, with a significant decrease in internal resistance, a decrease in rotational speed, an increase in current, and a decrease in the overall performance of the motor of about 15%. [Conclusion] Through the design and prototype test verification of the joint motor, it can ensure that the nuclear industrial robot can perform long-term operation and maintenance in a high-radiation environment, and the test magnitude reaches 5 MGy, which fully meets the current application requirements of radiation environment robots. With the increase of radiation level, the performance of the motor shows a decreasing trend, but it is still in a controlled state. This study provides certain reference and support for the development of motors in the nuclear field.