Objective To evaluate the effect of single injection of low dose zoledronic acid on bone resorption.Methods332 menopausal patients with bone deficiency treated in our hospital were selected.The patients were treated with zoledronic acid 1mg (1mg group), 2.5mg treatment group (2.5mg group), 5mg treatment group (5 mg group) and placebo treatment group (control group), each group of 83 patients.The patients of 1mg group, 2.5mg group and 5 mg group were treated with 1mg, 2.5mg and 5mg zoledronic acid alone.The patients in the control group were given intravenous infusion of placebo.Evaluated the lumbar spine (L1-L4) and total hip bone mineral density (BMD) and bone metabolic markers at baseline, 6, 12, 18, and 24 months in the four groups.The bone metabolic criteria included t β-Cterminal-telopeptide of type I collagen (β-CTX) and procollagen type-I N-terminal propeptide (P1NP).ResultsThe Lumbar spine BMD and the Total hip BMD were significantly higher in 1mg group than baseline value and Simultaneous valueand in the control group (P<0.05), The difference were statistically significant (all P<0.05).The values at 8 and 24 months decreased gradually.The value was significantly lower (P<0.05) compared with the control group, There were no statistically significant difference compared with the simultaneous value in control group.The lumbar BMD and the total hip BMD in 2.5mg and 5mg groups were significantly lower than the baseline values during the whole trial period (all P<0.05).The trend of β-CTX and P1NP was similar to that of BMD in each group.ConclusionIntravenous injection of 1 mg and 2.5 mg of zoledronic acid produces anti-bone resorption that can last for at least 1 year.After one year of treatment, The effect of single injection of 2.5 mg of zoledronic acid on bone is similar to that of single injection of 5 mg zoledronic acid.1 mg zoledronic acid produced by anti-bone resorption can last for 12 months, and then slowly disappear.