Abstract: Mg /TCP composites with different fraction of TGP were prepared through powder metallurgy and extrusion process.Through electrochemical test and immersion corrosion test,the corrosion properties of the composites in HBSS were studied.The topology and crystal structure of as-corroded samples were investigated by using SEM and XRD,respectively.It was shown that TCP increased corrosion resistance of the MgTCP composite.But the effect of TCP content on the corrosion resistance was non-linear.After immersed in SBF for 3d,HA was formed on the surface of the MgTCP composite but not on the surface of pure Mg.The HA deposition inhibited the corrosion of the composites to some extent,leading to the decrease of the corrosion.