Abstract: The space manipulator is widely used in the cabin docking and on-orbit servicing and works in a microgravity condition, so it is required to simulate the micro-gravity environment on the ground in developing space manipulators. The paper reviews overseas and domestic researches of the zero-g test environment. According to the test requirements, a zero-g simulation system based on the suspension system is proposed, which can realize the ground test and verify the capability and the reliability of a large space manipulator. Its suspension mechanism subsystem, the two-dimensional tracking subsystem, the constant tension subsystem, and the position & attitude measuring subsystem are discussed in detail.