The electrical signal acquisition system is the main component of the welding equipment,and the collected electrical signals can be used for the welding process and the analysis of the welding effect. According to the principle of wavelet packet denoising,this paper designs the electrical signal acquisition circuit,selects the appropriate acquisition card module,builds the welding electrical signal acquisition system device and uses this system to carry out the aluminum alloy double pulse MIG welding test. Pulse current and corresponding time parameters are collected into several typical electrical signal waveforms such as smooth transition of welding process,fast wire feeding,large droplet transition and arc breaking,and the corresponding appearance of weld appearance. The results show that by performing wavelet filtering and analysis on the collected electrical signals,combined with the quality of the weld,the welding parameters can be obtained by changing the welding current waveform parameters,thus verifying the importance of the collection of welding electrical signal to the welding process.