Abstract: Double-pulsed gas metal arc welding machine was developed based on both static-frequency and dynamic-frequency models.The feasibility of the models was proved and an expert database was developed based on welding experiments.The results indicate that:the accuracy can be guaranteed to 1 A for the current range 50-300 A of double-pulsed welding of Al continuous adjustments can be achieved by adjusting dominant role of the number of pulses and the subsidiary role of the base-current value.Moreover,by using this method,the current can be adjusted slowly for low welding current,and rapidly for high welding current.The adjusting range of welding current can be kept constant and continuous for the dynamic-frequency mode.The fish scale pattern weld with proper density scaly can be obtained by adjusting the modulation frequency.The welding currents are kept stable and there is interruption arc and little spatter,the welding seams are beautiful.