Objective To study the effect of bone mineral density (BMD) change on response of human spine to landing impact by numerical simulation. Methods The three-dimensional material point model of human head skull, cervical vertebrae, thoracic, lumbar vertebra, pelvis, ligament and disc was constructed from the computed tomography (CT) scanned images, and they were attached together as a human spine model and placed on the backrest of the chair, which was constructed by the MPM3D program. The acceleration loading was applied on the back rest of the chair to simulate the landing impact loading when the human spine model was laid on the back of the chair. The different responses of human spine to landing impact were simulated by changing the BMD and the corresponding elastic modulus. Results The general risk of injury γ value of normal BMD was 1.589 3, and when the BMD was reduced by 2%, 4%, 6%, 8%, 10%, respectively, γ values were 1.608 6, 1.634 7, 1.641 0, 1.662 5, 1.680 5, correspondingly. Conclusions Under the same landing impact loading, the smaller the bone mineral density, the larger the response of human spine to landing impact loading, and human body is more vulnerable to injuries.