Abstract: In this paper, double-layers laser-MIG welding of thick aluminum alloy method was put forward. It welds two layers:the first layer padding welding, to solve the problem of inadequate weld penetration; second welding surface for the cap to address the problem of the poor weld shape. The results showed that:rated at 4 kW lasers when the composite layer by laser-MIG welding materials, welding ZL114A deeps up to 10mm, average joint tensile strength is 238 MPa, tensile strength is greater than 80% of the base metal. Double-layers laser-MIG welding method of welding, a simulation of a cylindrical pieces of aerospace products, forming a good weld, penetration up to 9 mm. With no crack, no incomplete penetration and lack of fusion, no visible inclusions, defects is mainly chain-like porosity, pore diameter less than 1mm, almost no distortion after welding.