TA15 titanium alloy bulk specimens are prepared from raw material of spherical powders by laser deposition manufacturing technique. The effect of annealing temperature on the tensile mechanical properties and microstructure characteristics of TA15 titanium alloys is investigated, and the fracture mechanism and α group deformation mechanism on both sides of grain boundary under different annealing temperatures are analyzed. The results indicate that, the α phase in alloy microstructure is in order after the annealing treatment, and the thickness of α lamellar layer does not change so much as the annealing temperature increases; the micro-hardness is affected by the amount of α phase while it does not vary much with temperature; the α group deformation mechanisms on both sides of grain boundary are different; the crack easily appears and extends in β phase; the tensile fracture mechanism along deposition direction is different from that along perpendicular direction and the former is ductile fracture but the latter is semi-cleavage-ductile fracture.