Objective: To analyze the biomechanical effects of gravity loading countermeasure garment on human lumbar intervertebral disc under microgravity environment. Methods: Based on CT images of a healthy adult volunteer, the finite element model of L4-5 spinal unit was established. Through the empty load and loading of 400N axial load for 4 hours on lumbar finite element model, the biomechanical effect of the non-intervention and gravity loading countermeasure garment were simulated respectively under microgravity environment. Results:, The central pore pressure, radial displacement and water content of the human lumbar intervertebral disc increased with time under microgravity environment. In the case of wearing gravity loading countermeasure garment, the central pore pressure, axial stress, radial displacement and water content of the lumbar intervertebral disc were reduced after 72 hours of cyclic loading compared with the non-intervention group. Conclusions: The microgravity environment may cause degeneration of the lumbar intervertebral disc. Wearing gravity loading countermeasure garment can help the astronauts to prevent the adverse effects of the microgravity on the spine to some extent.