Abstract: Current research status of the bond strength and solubility of graded hydroxyapatite coatings produced by plasma spraying is summaried.The functionally graded hydroxyapatite coatings can increase the bond strength between the hydroxyapatite coatings and the substrate,and decrease the dissolution of coatings in simulated body fluid.Since the surface layer is hydroxyapatite,the resultant graded coatings show good biocompatibility.Ti-6Al-4V or ZrO2,or TiO2 in the graded coatings contribute to high bond strength.Post heat treatment is used for increasing the crystallinity and bond strength of the coatings.