There are three kind of welding method of underwater welding, they are underwater dry welding, underwater local dry welding and underwater wet welding, in which, the wet welding has been gained compressive attention for its easy and convenient operation. The properties of different wet welding are introduced at first. And then, the research development and achievements of wet welding are discussed from three aspects, which are welding rod study, arc stability study and welding shape modeling. At last, some suggestions are proposed that we should increase the study on the wet welding special sensors and arc discharging mechanism, and so as to promote high quality development of wet welding.