The invention discloses an aluminum alloy laser oscillation welding method, which belongs to the technical field of welding. The method comprises the step of welding by adopting an oscillating laser beam, wherein the oscillating laser beam moves forward along an axis which is parallel to the welding direction during welding, the oscillating laser beam oscillates in a reciprocating mode on both sides of the axis when moving forward so as to form a zigzag motion path, the oscillating amplitude of the motion path on the both sides of the axis is the same, and the motion path is formed in a way that a plurality of motion path units are repeatedly arranged. According to the aluminum alloy laser oscillation welding method, internal cracks and pore defects of aluminum alloy laser welding beams can be effectively avoided, the welding beams formed by welding are smooth in transition, and the overall mechanical properties of the welding beams are good.