The effects of laser melting deposition process parameters (laser power and powder feeding rate) controlled by PLC on the phase composition, microstructure, and tensile properties of TC4 titanium alloy were studied by means of X-ray diffractometer, metallographic microscope, and tensile testing machine. The results show that under different laser power and powder feeding rate, TC4 titanium alloy is mainly composed of α phase harmony β phase. With the increase of laser power or the decrease of powder feeding rate, the β phase of TC4 titanium alloy will gradually change into α phase. The density of TC4 titanium alloy increases with the increase of laser power and decreases with the increase of powder feeding rate. With the increase of laser power or powder feeding rate, the tensile strength, yield strength, and elongation of TC4 titanium alloy increase first and then decrease. The maximum value is obtained when the laser power is 1 400 W or the powder feeding rate is 1.1 r/ min. When the laser power is 1 400 W and the powder feeding rate is 0.9 r / min, the tensile strength, yield strength, and elongation of TC4 titanium alloy are 1 212 MPa, 1 150 MPa and 9.4% respectively. When the strength is higher than that of as-cast and forged & annealed TC4 titanium alloy, and the elongation is significantly higher than that of TC4 titanium alloy melted by selective laser, and TC4 titanium alloy deposited by laser melting has good strength and plasticity, which is mainly related to the high density and relatively small α and β microstructure of TC4 titanium alloy.