Abstract: Objective The aim was to solve the issues of poor strength-toughness matching and low toughness in the as-deposited TC4 titanium alloy fabricated by laser powder bed fusion (LPBF). Methods In this study, the microstructure is regulated through heat treatment and hot isostatic pressing to balance strength, plasticity, and fracture toughness, thereby achieving excellent comprehensive mechanical properties. Results The results show that the LPBF TC4 titanium alloy forms large columnar grains growing along the direction of melt deposition, with the interior of these grains composed of metastable acicular martensite α' phase, exhibiting relatively high tensile strength but low fracture toughness ranging from 40.5 MPa·m^1/2 to 42.5 MPa·m^1/2. After heat treatment at 800 °C, the α' phase within the β grains of the LPBF TC4 titanium alloy transforms into a lamellar α phase, resulting in a decrease in tensile strength but an increase in elongation and fracture toughness. After hot isostatic pressing at 940 °C, the width of the lamellar α phase further increases to 2 μm–5 μm, reducing the tensile strength to approximately 900 MPa, but effectively preventing straight crack propagation and thereby improving fracture toughness. Conclusion Through hot isostatic pressing, the fracture toughness of the LPBF TC4 titanium alloy can be increased to over 80 MPa·m^1/2, meeting the service requirements of aerospace components.