Abstract: Objective To observe the effects of pulsed electromagnetic field (PEMFs) or/and exercise on the area bone mineral density (aBMD) and volume bone mineral density (vBMD) of rats with osteoporosis induced by tretinoin gastric perfusion.Methods 100 female SD rats were randomly divided into 5 groups with 20 rats in each group： PEMFs group, exercise group, PEMFs plus exercise group, osteoporosis group and healthy control group. Except for the healthy control group, the osteoporosis models of other 4 groups were built by tretinoin gastric perfusion. After the building of models, each group was intervened with different treatment. In the 4th, 6th and 8th week after treatment, relevant Results of aBMD and vBMD were tested.Results Compared with the osteoporosis group, the BMD of the rats of PEMFs group, exercise group, PEMFs plus exercise group significantly increased significantly ( P＜0.05) in the 6th week, 4th week and 4th week after treatment respectively. In the 6th and 8th week, there was no significant differences among the PEMFs plus exercise group, the exercise group and the PEMFs group ( P>0.05).Conclusion PEMFs can increase the BMD of the rats with osteoporosis as well as exercise. PEMFs takes effect slower than exercise.

Key words: pulsed electromagnetic field (PEMFs), exercise, osteoporosis, tretinoin, bone mineral density （BMD）