Titanium alloy solid welding wire was developed by optimizing the synergistic mechanism of Cr-Mo-Zr. The liquid bridge transition with uniform droplet stress and stable droplet transition was selected for laser wire filling welding. Finally, the high quality welding of 20 mm thick Ti64 titanium alloy plate was realized. Results show that Ti-Al-Cr-Mo-Zr titanium alloy solid welding wire has enough stiffness and relaxation, which provides a guarantee for the accurate alignment between the beam and the welding wire, and stable wire feed during the subsequent laser wire filling welding. In the welded seam, the proportion of large-angle grain boundaries greater than 10° is 97.8%, the geometrically necessary dislocation density is low, and the proportion of small size grains is relatively large. The overall orientation of the welded seam is not strong, the texture is not obvious and the distribution is random, and the maximum multiples of uniform distribution is only 12.66. The average tensile strength of welded joints is 901 MPa, the average elongation is 21%, and the impact toughness at room temperature ranges from 29 J to 33 J. The self-developed and designed Ti-Al-Cr-Mo-Zr titanium alloy solid welding wire plays an important role in obtaining welded joints with synergistic optimization of strength and plasticity-toughness, and provides basic technical support for the long-term safe service of titanium alloy welding structures.