Objective To study the effects of the compound medicine of icariin and puerarin on peak bone mass in rats during growth period, and to explore its possible mechanism. Methods Forty female Sprague-Dawley rats aged 1 month were randomly divided into normal control group(C), icariin group(I), puerarin group(P), icariin and puerarin compound groupc(I+ P), 10 in each group. The body weights were recorded once every two weeks, and the bone mineral density was measured by dual-energy X-ray absorptiometry every month. After the bone mineral density of the whole body was significantly different between the control group and drug groups, the animals were sacrificed. The right femur and vertebrae were separated to measure the bone mineral density. The biomechanical properties of the femur and vertebra were detected by AG-IS series desktop electronic universal testing machine. The bone formation index osteocalcin, PINP and bone resorption index were determined by ELISA. Changes in the contents of tartrate-resistant acid phosphatase 5b(TRACP 5b) and CTX-1; and changes in trabecular bone related parameters were recorded after magenta-picric acid staining. Results There was no significant difference in body weight between the two groups (P>0.05). There was no significant difference in whole body bone density after 1 month of treatment (P>0.05). After 2 months of treatment, the body bone density of the drug-administered group was higher than that of the control group. Whole body bone density, femur and vertebral bone density, femur maximum load value, maximum vertebrae load value and trabecular bone number and area, serum OC and PINP levels increased, while TRACP 5b and CTX-1 levels decreased(P<0.01) in drug group. The difference from the control group was statistically significant (P<0.05). There were significant differences in biochemical parameters and bone histomorphology between the compound drug group and the two-flavor monomer group (P<0.01). There was no significant difference in bone mineral density and biomechanics, but the average value was higher than that of the monomer group. Conclusion The combination of icariin and puerarin can effectively increase the peak bone mass in rats. Key words: Icariin; Puerarin; Compound; Peak bone mass; Rats