Abstract: Double-pulse MIG welding of aluminum alloy can improve the efficiency of welding and meanwhile get beautiful weld surface with scaly figures.Based on single-pulse welding, the experiments of double-pulse MIG welding of aluminum alloy were carried out by changing the current, high-frequency, low-frequency and welding velocity of the power which is the self-developed double-pulse MIG welding inverter power.Tests shows that strong/weak pulse peak current and high-frequency have great influence on the stability of welding process and spatters.When the difference between strong and weak pulse peak current is 40 A and high-frequency is 250 Hz, the weld forming is good.To a certain extent, the width of the scaly figure on the weld surface is directly related to low-frequency and welding velocity: the width of the scaly figure will decrease with the improvement of low-frequency and widen with acceleration of welding velocity.An empirical formula reflecting the relationship between low-frequency, welding velocity and the width of the scaly figure through statistical methods is obtained, and the results show that when the ratio of welding velocity to low-frequency is from 0.19 to 0.30, the width of the scaly figure is from 2 to 3 mm, which means good welding performance.