Abstract: Underwater wet flux cored wire welding (FCAW) plays an important role in the maintenance of marine facilities due to its good operational applicability and other advantages. The dynamically changing bubble growth around the welding area will affect the stability of the welding arc. An underwater wet welding test platform was built and wet flux cored wire welding experiments was conducted. Sensors was used to synchronously collect the arc current and voltage signal, the bubble sound signal and the bubble high-speed image in the welding process The contrast relationship between the bubble acoustic signal and the high-speed bubble image was studied. The bubble acoustic signal and the arc current voltage signal were analyzed simultaneously. The evolution behavior of the bubble under different arc combustion conditions was obtained. The effect of bubble evolution on the steady state combustion of underwater wet welding arc was reflected from the change of bubble acoustic signal. The results show that the bubble acoustic signals can clearly reflect the various states of welding arc combustion, can classify different bubble evolution patterns, and analyze the corresponding relationship with arc combustion characteristics.