Ti–6Al–4V is suitable for a variety of additive manufacturing technologies, but the organizational evolution forms of Ti–6Al–4V manufactured by different additive technologies are different. In this work, selective laser melting with the lowest deposition efficiency and wire arc additive manufacture with the highest deposition efficiency are studied. The differences in evolutionary form of microstructures and mechanical properties of Ti–6Al–4V under these two conditions were summarized. The Ti–6Al–4V microstructure manufactured by selective laser melting is dominated by α' martensite, which reduces its ductility. The grain size of Ti–6Al–4V manufactured by wire arc additive manufacture is large and has grain boundary α, resulting in low strength. In order to solve these problems, the effective methods to improve the performance were proposed. Meanwhile, the development and future research trends of these two additive technologies were predicted.