Abstract： Objective To explore the efficacy of alendronate sodium combined with alfacalcidol in the treatment of primary osteoporosis.Methods Between January 2000 and January 2006,clinical data of 156 elderly patients with primary osteoporosis registered in our hospital were retrospectively analyzed and divided into treatment and control groups (n=78 each).The oral administration of calcium carbonate D3 was taken in the control group for 12 months,while the combined treatment by oral administration of calcium carbonate D3,alendronate sodium and alfacalcidol was taken in the treatment group for 12 months also.The bone mineral density(BMD) of lateral lumbar vertebra (L2-4) and left femoral neck,the levels of serum bone gla protein (BGP) and β-Crosslaps(β-CTX) were compared between two groups before and after treatment.After the following up of 3-5 years,the incidence rates of bone fracture were compared between two groups.Results In the control group,any obvious changes in BMD of lateral lumbar vertebra (L2-4) was not found (P＞0.05),while the BMD of left femoral neck significantly decreased [(0.52±0.07) g/cm2 vs (0.56±0.09) g/cm2,P＜0.01],and no change in serum BCP was found (P＞0.05),while the serum β-CTX increased [(0.51±0.17) mg/L vs (0.40±0.12) mg/L,P＜0.01] after treatment.In treatment group,the BMD of left femoral neck and lateral lumbar vertebra (L2-4) were mcreased [(0.72 ± 0.12) g/cm2 VS (0.55+0.08) g/cm2,(0.92±0.17) g/cm2 VS (0.76±0.13) g/cm2,both P＜0.01],serum BCP increased [(6.31± 1.32) μg/L vs (4.19±1.07) μg/L,P＜0.01] and serum β-CTX decreased [(0.26±0.11) mg/L vs (0.55±0.31) mg/L,P＜O.O1] after treatment.The following-up data showed that the incidence rates of bone fracture were 3.8％(3/78) in treatment group and 21.8％ (17/18) in control group,with a significant decrease in treatment group (P＜0.05).Conclusion The efficacy of alendronate sodium combined with alfacalcidol is good in the treatment of primary osteoporosis,which may reduce the incidence rates of bone fracture.