Abstract: Under water deep environment, underwater wet flux cored wire welding (FCAW) welding is affected by the growth of the surrounding arc bubbles, and its state needs to be collected through signal. The article first builds an underwater wet welding test platform to conduct a wet flux-cored wire welding experiment. The bubble sound pressure signal, high-speed camera signal, and arc current and voltage signal in the welding process are collected synchronously; then, the arc ignition stage is compared. The dynamic evolution images of bubbles in shallow water and 20 m depth and their sound pressure signals, combined with the 20 m depth arc stabilization phase signal, it is found that the bubble pulse sound signal and the bubble image have a good corresponding relationship in the evolution details such as bubble size, blasting period, etc. As the water depth increases, soot causes the image signal to become more blurred. Finally, a comparative analysis of the acousto-electric signals from the arc starting to the arc stabilization stage obtained in the environment of 20 and 40 m underwater, shows that the bubble sound pressure signal can clearly reflect the changing state of the bubble, and the deep underwater sound pressure signal It is feasible to replace high-speed cameras.