Abstract: Because the gravity on the surface of the earth is quite different from that on the flight orbit or on the surface of other planets, the performance and the reliability of a space mechanism should be tested and verified on the ground before launch. The gravity environment for a practical working state should be simulated correctly in ground tests for space mechanisms; therefore, it is necessary to have a ground gravity compensation equipment. This paper discusses the basic types of this kind of equipment, and the principles of commonly-used equipment with examples. The related practical engineering experience is reviewed.