Abstract: Two series of specimens are designed for 5 A06 aluminum alloy（ AA） lap joints welded by Tungsten Inert Gas（ TIG） welding. The tensile and shear mechanical properties of 5 A06 TIG welding lap joints with different thickness and widths are obtained. The test results indicate that the tensile and shear strength of 5 A06 TIG welding lap joints decrease obviously with the increase of the thickness. The tensile strength of 5 A06 TIG welding lap joints with a thickness of 2 mm is about 67% of that of the parent material,while the shear strength is about 73. 5% of that of the parent material. Scanning electron microscope is used to observe and to compare the fracture morphology of test specimens under different stress states.The comparison demonstrates better toughness in tensile specimens. The research results provide test data and reference for structural design utilizing 5 A06 TIG welding lap joints.