Objective To study the clinical effect of Longniu Bubi Granule on prevention and treatment of bone loss caused by premenopausal ovarian function suppression (OFS) combined with breast cancer aromatase inhibitor (AIs).Methods Forty patients with postmenopausal and high risk of breast cancer treated with OFS combined with aromatase inhibitors were divided into treatment group (n=23) and control group (n=17).The two groups were treated with calcium VitD3125IU,1 tablet per day.The treatment group received the additional of Longniu Bugu Decoction,2 doses daily,with continuous medication for 6 months.The bone mineral density (BMD) level,bone mineral density (T) and serum bone alkaline phosphatase (BALP) were measured before and 6 months after treatment.Results There were significant differences in lumbar (L2-4) and femoral neck bone mineral density,bone mineral density (T) and serum bone alkaline phosphatase (P＜0.05) between the two groups after treatment,and the treatment group was superior to the control group.Conclusion Longniu Bugu Decoction can reduce bone loss in patients with premenopausal breast cancer caused by OFS combined with AIs therapy and improve patients' life quality.