Abstract: A welding parameter collection and analysis system which is based on NI Virtual Instrument is described.A welding current and welding voltage signal collection circuit is designed.For farther research demarcated signals are added to represent different welding period.This article introduces software flow chart of the system in detail.The system can collect and display signals in real-time,and use the statistical analyzing method to transfer current and voltage signals into accessible format.By this means,the welding process' characteristic parameters can be extracted out and shown in the probability density distributing diagrams.Experimentations prove that this system works in stabilization,satisfy the CO₂ arc welding process,and the collected data is full and credible.