The effects of three heat treatment methods which include annealing, solution hardening of two-phase regions, and solution and aging treatment on the microstructure and mechanical properties of TC4 titanium alloy formed by selective laser melting (SLM) are investigated. The results show that the fine acicular martensite is formed in the TC4 titanium alloy formed by SLM and there is nearly no β phase, which makes the TC4 titanium alloy have high strength and poor plasticity. After the 840 ℃/2 h/air-cooling (AC) annealing, the microstructure of TC4 titanium alloy is consisted of (α+β) phases, which makes TC4 titanium alloys have better strength and plasticity. After the 940 ℃/1 h/water-quenching (WQ) solution hardening, the staggered basket-weave (α+β) microstructure is obtained in TC4 titanium alloys, the strength decreases significantly and the plasticity increases because of the increase of β phase content and grain size. After 940 ℃/1 h/WQ+540 ℃/4 h/AC solution and aging heat treatment, the (α+β) phases are formed and uniformly dispersed, and the α phase coarsens, which result in the decrease of strength and the slight increase of plasticity. After heat treatment, the residual stress and the tendency of the strain cracking of TC4 titanium alloy decrease. The better strength/plasticity matching of TC4 titanium alloy formed by SLM can be obtained by the annealing heat treatment of 840 ℃/2 h/AC.