The combination of pulsed Nd:YAG laser and continuous diode laser could perform high-performance micro-welding for aluminum alloy, since the continuous diode laser made it possible to keep the high temperature during an interval time of laser irradiation. Therefore, the high-efficient absorption of pulsed Nd:YAG laser energy would be expected, and 15% increase in the bead width and 150% increase in the penetration depth could be achieved with better surface integrity. In addition, a pulsed Nd:YAG laser was absorbed effectively from the beginning of laser scanning by the pre-heating pulse of pulsed Nd:YAG laser with the superposition of continuous LD. The combination of pre-heating pulse and continuous LD made the welding phenomenon stable from the beginning of laser scanning. Moreover, the appropriate post-heating by the continuous diode laser led the reduction of crack generation with the control of temperature history.