To investigate the temperature rise caused by loss of the magnetically suspended control moment gyroscope for the spacecraft application, it is necessary to analyze and calculate the loss and temperature distribution. In this paper, theoretical loss models that consider the iron and copper losses were established. The losses in a single gimbal magnetically suspended control moment gyroscope (SGMSCMG), which consists of a frame torque motor, radial magnetic bearing, axial magnetic bearing, high-speed motor of rotor system, with a rated speed of 12 000 r/m and maximum angular momentum of 200 N·m·s were calculated. These losses were then used to determine the temperature distribution, which was based on a three-dimensional finite-element model. A thermal-structure coupled simulation analysis was also performed. The results reveal that the maximum temperature occurs at the stator of the high-speed motor and has a value of 48.3 ℃. Finally, the temperature rise of the prototype is verified by experiment. According to the experiments, the maximum temperature occurs at the stator of the high-speed motor, and its maximum value is 51.8 ℃. The error is 6.8% when the experimental results are compared with predicted values. The loss calculation and finite element analysis of the thermal field are verified by the temperature rise experiment. The experimental results provide theoretical reference for overall structure optimization.