Abstract: Zn powder, Mg powder and nanometer hydroxyapatite（hydroxyapatite, HAp） were used as raw materials.Zn-15Mg/xHAp（x =0, 5, 10wt%） composites were successfully prepared by high energy ball milling and spark plasma sintering（spark plasma sintering, SPS）. The effects of different HAp content on the density, microstructure and degradation behavior of the composites in vitro were studied. The results show that, the density of composites prepared by SPS is more than 90%. The results of static immersion test in vitro show that, the degradation rate of composites in Hank’s solution increases with the increase of HAp content. Among them, the performance of Zn-15Mg/5HAp is the best, and the corrosion rate is stabilized at 1.8 mm/a after 10 days of immersion. At the same time, it is found that increasing the content of HAp can improve the deposition effect of calcium and phosphorus layer on the surface of the material during the degradation process,and make the calcium and phosphorus layer uniform and continuous.