The invention provides a terminal sliding-mode control method for a suspended six-freedom-degree microgravity environment simulation system. The six-freedom-degree microgravity environment simulation system is composed of a simulation spacecraft, an unconstrained suspension device, a buffer device, a sensing measuring unit, a Z-direction module, a Y-direction module, an X-direction module and an implementation control unit. Based on the working principle, a coordinate system is established. A Lagrangian equation is used to carry out modeling on the system. Based on the Lagrangian model, the provided terminal sliding-mode control method for the suspended six-freedom-degree microgravity environment simulation system has the advantages of anti-interference, good robustness and high simulation precision. Environments different from the earth in gravity, such as the moon and the Mars, or the microgravity environment in space can be simulated, which ensures that the environment of the spacecraft ground experimental verification is the same as the working environment.