Abstract: Twelve female New Zealand white rabbits of 7 months old were subjected to oophorectomy. Before the oophorectomy the activities of serum alkaline phosphatase，acid phosphatase and bone - specific alkaline phosphatase were 20.06±8.20,19.06±5.46 and 14.04±1.67U/L respectively and declined significantly to 14.60±4.64，11.04±4.10 and 4.44±2.10 U/L respectively 8 months after oophorectomy(P＜0.001). Since the decline in bone -specific alkaline phosphatase activity far exceeded that in the alkaline phosphatase activity, the former could be used as a sensitive special index for bone metabolism. The decline in bone - specific alkaline phosphatase also exceeded that in the acid phosphatase activity. The results suggest that the activities of these enzymes can be considered as a part of the biochemical parameters for osteoporosis in postmenopausal women.