The invention discloses an assisting method and device for movements in space. According to the assisting method and device, the moving ability of astronauts can be effectively enhanced. According to the method, an external skeleton system is coupled on a space suit. The external skeleton system comprises a profiling mechanical structure, a man-machine interface system, a control system, an actuator and an energy power system. The man-machine interface system senses and sends moving states and moving intensions of the astronauts to the control system, the control system processes information and sends instructions to the actuator, and the actuator drives the profiling mechanical structure to assist in supporting of astronaut loads or providing of boosting power for movements of the astronauts, accordingly, energy consumption of the astronauts is greatly reduced, the bearing ability, the moving ability of upper and lower limbs and the information processing ability of the astronauts are improved, the adaptability of the astronauts to severe environments is enhanced, and the astronauts are assisted in completion of various space operations. Besides, by the aid of the profiling mechanical structure, astronaut bodies can be protected, the astronauts are prevented from being injured, and the assisting method and device are suitable for popularization in the of astronaut space operation devices.