5A06 aluminum alloy bottom-locking joint with a thickness of 3 mm was welded by beam one-dimensional weaving laser. The influence of beam weaving width, beam weaving frequency, welding speed, and beam defocusing distance on porosity rate of the weld were analyzed. The results show that as the beam weaving width and beam defocusing distance increase, the porosity rate decreases significantly. As the beam weaving frequency increases, the porosity rate firstly decreases and then increases. The best beam weaving frequency range is from 150 Hz to 250 Hz. As the welding speed increases, the porosity rate firstly increases and then decreases. The porosity rate and depth-to-width ratio of the weld are generally exponential growth relationships. The porosity rate can be controlled within 5% when the depth-to-width ratio of the weld is less than 1.5. On the basis of porosity analysis, the optimization process specification was obtained. By using this specification, the product sample was welded, and the porosity rate of the weld meet the Class I requirements of the relevant standard.