The outer wing wall of civil aircraft is usually constructed with T-truss structure. The long girder connection structure at the root of the wing is a vital force transmission structure. The long truss structure at the root of the wing is mainly connected with the corresponding corner box. In this paper, the evolution rule, mechanical properties, and defects of titanium alloy long girder angle box of civil aircraft were studied by using laser stereotyping technology. The internal microstructure of the furnace sample is small rod-shaped α phase, there is no anisotropy in performance, and is net basket structure. The tensile strength of the test block in the X、Y and Z directions is higher than 889 MPa, and the degree and dispersion of its deviation from the average tensile strength in three directions of X、Y and Z are not exceeded over 5%, indicating good overall performance; The tensile fracture of the sample belongs to ductile fracture, and the tensile fracture is composed of three parts: fiber zone, radiation zone, and shear lip zone. Fatigue fracture is plastic fracture, and in fatigue fracture, secondary cracks are continuous and dense. The size and forming quality of the processed sample meet industry usage requirements.