Objective To analyze the biomechanical effects of gravity loading countermeasure garment on human lumbar intervertebral disc in microgravity environment. Methods Based on CT images of a healthy adult volunteer, the finite element model of L4-5 vertebrae was established. Through the empty load and 400 N axial loading for 4 hours on lumbar finite element model, the biomechanical effect of the non-intervention and gravity loading countermeasure garment were simulated respectively in microgravity environment. Results The central pore pressure, radial displacement and water content of the human lumbar intervertebral disc increased with time in 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 Wearing gravity loading countermeasure garment can help astronauts to prevent the adverse effects of microgravity on the spine to some extent in microgravity environment.