This study uses vertical compressive tests to observe the protective effects of different recombinant human growth hormone on for upper tibian mechanical properties of rats 3 months after ovariectomy and compared with estrogen therapy. Results:1.mechanical strength of upper tibiae obviously decreased after ovariectomy. 2.Middle and high doses of growth hormone could obviously increase mechanical strength of upper tibien of OVX rats.3.Estrogen and low dose of growth hormone had no influence on upper tibiae mechanical strength of OVX rats. The protective effects of growth hormone may be contributed to increment of bone mass of cancellous and cortical bone.