Abstract: A local dry underwater weld method was proposed in this paper for the underwater structures horizontal welding. Through designing the structure of waterproof chamber, a flowing up wind field was formed, and this wind field was used to reduce the molten pool dropping during horizontal welding process. A high speed camera was used to record the metal transfer process, then the characteristic of metal transfer of GMAW in the local dry environment was researched. The results show that B type short circuiting transfer more easily happened in the local dry welding environment. In the globular transfer status, due to the mass of droplet was relatively large, the lateral wind had less influence on the droplet. The droplet transfers into molten pool along downwards direction. In the spray transfer status, the lateral wind had less influence to the welding arc but make the droplet transfer into the molten pool slightly along a upward direction. It was beneficial to depress the molten pool dropping during horizontal welding process and improved the welding bead forming quality. The results had certain reference value to improve the horizontal welding quality.