In order to investigate the effect of yak bone powder on bone mineral density (BMD), bone metabolism and physical function of athletes, 45 athletes from fencing, modern pentathlon, martial arts and boxing were selected as research subjects. Athletes took 5g yak bone powder daily, 6 times per week, for 4 weeks. The BMD of forearm and calcaneus bone were detected by EXA-3000 peripheral dual energy X-ray bone densitometer, and the blood biochemical indexes were detected by venous blood sampling. The results show that the BMD of the right calcaneus of the male athletes is increased significantly (P < 0.01), the BMD of the forearms and calcaneus of the women athletes are higher than before taking (P < 0.01, P < 0.01, P < 0.01, P < 0.05). After taking yak bone powder, the serum Ca and P of women athletes are decreased significantly (P < 0.01, P < 0.05), Ca of male athletes is decreased significantly (P < 0.05), the CK of female athletes is decreased significantly (P < 0.01), the IgM of male athletes is increased significantly (P < 0.01). It is concluded that taking yak bone powder of 4 weeks can improve the BMD of the female athlete"s forearm and calcaneus, it has little effect on the BMD of male athletes" forearm and calcaneus, and has no adverse effect on the biochemical indexes of bone metabolism and immunoglobulin, and can better maintain the physical function level of athletes.