Abstract: Objective To study the effect of Ca supplement on the mineral density(BMD),serum TRAP and AKP of osteoporosis and provide the evidence on how to treat and prevent osteoporosis.Methods Twenty five helathy pregnant SD rats were randomly divided into 5 Groups.Groups 2,3,4 and 5 were reproduced with patterns of animal osteoporosis.The diet in group 1 and group 2 was the basic diet,while the groups 3,4,5 experiment diets were supplemented with Ca.After born,selected 3 young rats live with the mother rate.The BMD,BMC,serum TRAP and AKP were measured 37 days later.Results The BMD and BMC level of young rats in Ca supplement group is higher than vigorous group.The serum TRAP and AKP in vigorous group were higher than Ca supplement group.Conclusion Ca supplementhas certain effects on the prevention of osteoporosis.