Abstract: The zero-g simulation device is designed by using suspender spring and counter weight,and the static gravity compensation formulas of space manipulator's detached body are deduced with gravity compensation theory.Based on the least minimum square theory,an optimization program of suspension force is developed,through which the optimization of multiple torques is transformed into the optimization of a whole target,and the numerical value of each suspension force can be obtained.The model of the zero-g simulation device of space manipulator is built in ADAMS when the length of suspender spring is 1 000 mm.Under the condition that the space manipulator is in stationary state,the relative errors between the optimization results and the simulation results are around 10%.And the bending torque and counter torque generated by the zero-g simulation device can meet the technical requirements when each joint of space manipulator moves at the constant angular speed of 0.5°/s and 1°/s.Therefore,this approach is suitable for zero-g simulation of space manipulator.