Aiming at the welding technology of TC4 titanium alloy formed by diffusion bonding with a thickness of (2.0+1.5) mm, the laser welding and TIG filler wire welding process research were carried out. The joints of the two welding methods were subjected to post-weld heat treatment at 650 ℃ to relieve stress. The microstructure of the joints of each method is analyzed, and the mechanical properties of the joints are tested. Results show that the two welding methods can obtain well-formed joints with appropriate processes. Compared with argon arc welding, the crystal grains of laser welding joints are smaller, and α′ phase is more. Laser welding shear strength and tensile properties parallel to the weld are higher than argon arc welding, but the bending strength and tensile properties perpendicular to the weld are lower than argon arc welding.