Taking the gravity compensation mechanism of the wearable robot space tandem mechanism as research object,a design method of centering the rotation center of the balance link and the axis of the compensator was proposed.A plane gravity compensation unit was designed in the yaw surface rotation of the balance link,then the compensation unit was modified into a space gravity compensation unit to adapt to the general rotation of the balance link.The gravitational potential energy of the tandem mechanism was regarded as the sum of the gravitational potential energy of multiple subsystems.The action mode of the space gravity compensation unit on the balance link and the compensation performance of deflection were analyzed.Finally,combining the space gravity compensation and synchronous belt structure,the gravity compensation mechanism of the space tandem mechanism was constructed.Through the simulation analysis of space gravity compensation,the gravity balance performance and the effectiveness of the proposed design method were verified.