Additively manufactured TC4 alloy has attracted extensive attention due to its short processing cycle, high dimensional accuracy and good forming quality. However, the research on its high-temperature mechanical properties and corrosion behavior in Cl- containing solution after heat treatment is relatively scarce. In this study, TC4 alloy was fabricated by selective laser melting (SLM). The microstructure, high-temperature mechanical properties and corrosion behavior of TC4 alloy after heat treatment were studied by optical microscope, scanning electron microscope, X-ray diffractometer, universal tensile testing machine and electrochemical testing, and compared with as-cast TC4 alloy. The results show that the phase composition of SLM is the same as that of cast TC4 alloy. The microstructure of SLM TC4 alloy is mainly lamellar (α+β) phase, with an average grain area of about 2 μm2, while the as-cast TC4 alloy shows a typical Widmanstatten structure, and the average grain area is about 276 μm2. Compared with as-cast TC4 alloy, SLM TC4 alloy possesses excellent mechanical properties at both room temperature and high temperature, and the passivation film formed on its surface has better protection performance, resulting in a lower corrosion rate.