Abstract: To improve the reliability of the real-time monitoring for laser welding,a multi-sensor signal sampling and processing system was built based on LabVIEW,a virtual instrument development tool.Three signals of audible sound(20Hz~20kHz),plasma optical emission(400nm~500nm),and infrared emission(1200nm~1600nm) during the laser welding process,were picked up and analyzed.Correlation analysis of the three signals shows that the two optic signals are synchronous and the audible sound signal is hysteresis to the optic signal.The hysteresis time is just equal to the sound transferring from welding point to senor,which proved the validity of the three detecting signals.Two examples show that the reliability of multi-sensor monitoring is higher than single sensor monitoring.So,the multi-sensor detecting and signal fusion is the developing direction for the laser welding monitoring in the future.