Abstract: Taking the welding current,arc voltage and arc spectrum as the information source,this paper designed a welding arc information measuring and processing system which can deal with data acquisition,signal processing,information extracting and sync high-speed photography.The welding current sensor and arc voltage sensor developed here can isolate heavy-current and weak-current which can protect data acquisition board and computer against heavy-current effectively and have good quality output signal.The arc spectral sensor designed in this paper can attain higher signal-to-noise ratio (SNR),and then results in better quality arc spectral signal.In terms of Visual Basic,the software can collect multichannel welding arc signal,then analyze them instantly and statistically in order to extract more valuable information.