Abstract: The purpose of the research was to explore the effect of donkey bone collagen peptide(DBCP) on improving osteoporosis in rats. Firstly, ovaries of healthy female SD rats were excised to construct osteoporosis model. Then different molecular weights of DBCP(<1 kDa, 1~3 kDa, >3 kDa) were used as the test samples, and the high and low dose groups(4%, 2%) were set respectively. After 12 weeks of feeding, the efficacy evaluation indexes(serum, organ and bone indexes, etc.) of each group were measured. The results showed that: DBCP with different molecular weight did not significantly affect the liver and kidney function of rats. The high-dose groups(4%) of DBCP with three molecular weights could inhibit the increase of alkaline phosphatase and tumor necrosis factor caused by metabolic imbalance after ovariectomy;<1 kDa and 1~3 kDa DBCP could improve the level of calcium and phosphorus in osteoporosis rats, and restore bone mineral density to normal level in ovariectomized rats. In conclusion, DBCP has a certain improvement effect on osteoporosis symptoms without obvious side effects, and can be taken as a safe nutritional supplement for a long time.