Abstract: The influence of annealing temperature on the microstructure and mechanical properties of TC4 alloy prepared by selective laser melting was studied.The experimental results show that this experimental TC4 alloy is composed of primary β columnar grains and diffusion-distributed acicular martensite α' phase precipitated in crystal. When the annealing temperature above 700 ℃, martensitic α' phase is decomposed into α+β phase. With the increase of annealing temperature, the microhardness and tensile strength of TC4 alloy decrease, but the elongation increases. After annealing at 800 ℃, the elongation of this experimental TC4 alloy is 9.79%and the tensile strength is 1146 MPa, which fully meets the requirements of aviation standards.