TC4ELI titanium alloy is widely used in integral load carrying components of aircraft due to its excellent strength, ductility and damage tolerance. However, due to the different primary β grain morphology and microstructure of TC4ELI titanium alloy component manufactured by additive manufacturing, different heat treatment methods are often required from forgings. Therefore, to obtain a suitable heat treatment method for additive manufacturing TC4ELI, the microstructure of as-deposited TC4ELI titanium alloy fabricated by laser additive manufacturing and the effect of hightemperature annealing on the microstructure and mechanical properties of laser additive manufacturing TC4ELI titanium were studied. The results show that with the increase of annealing temperature in the dual-phase zone, the width of primary α phase increases, the content of primary α phase decreases, and the secondary α participates. After the single-phase zone annealing, TC4ELI titanium is still ultrafine basket-weave microstructure. The microhardness and yield strength of TC4ELI titanium alloy after annealing in the dual-phase zone decreases slightly, the tensile strength increases slightly, the ductility dose not change much, and the anisotropy dose not improve significantly. However, the strength increases slightly and the ductility decreases significantly after annealing in the single-phase zone. Different from the annealing of forging TC4ELI in the single-phase zone, the strength and ductility matching of additive manufacturing TC4ELI is better after annealing in the dual-phase zone.