The microstructure of the titanium component in hydroxyapatite (HA)-Ti asymmetrical functionally graded biomaterial (FGM) fabricated by powder metallurgical process was investigated.It is found that the main subthere of the Ti component in the FGM consists of screw dislocations whose Burgers vectors are 1/3and there are not deformation twins. Screw dislocations are straight and regularly distributed, and cross slip can be observed. The density of the dislocations in the Ti component increases with the rise of the content of the HA component in the FGM. The subgrain boundaries of the Ti component consist of dislocation network walls. Some microbands with bamboo-leaf-shape distribute regularly in Ti grains, which exhibit a specific orientation relationship with α-Ti parent phase.