In order to improve the deterioration of the microstructure and properties of the weld caused by the rapid cooling rate during the solidification of underwater welding. In this experiment， the local dry underwater welding of 2205 duplex stainless steel was carried out by using adjustable ring laser. Meantime, compared with the on land welds, the effects of different proportions of center and ring laser on weld formation, microstructure and mechanical properties were studied. The results indicated that the center laser mainly affected the penetration depth. And as the proportion of central power increased, the degree of oxidation on the weld surface became severe and the surface roughness increased. In terms of microstructure, compared with the same parameters on land, the Widmanst?tten austenite content of the underwater weld increased, and the number of intragranular austenite decreased or even disappeared. With the increase of the proportion of ring laser, the austenite content in the weld had no obvious change, the grain size and aspect ratio of the weld decreased, the directionality of columnar crystal growth on both sides of the weld decreased, and the number of LAGBs increased. In terms of performance, the tensile strength of underwater joints was slightly higher than that on land, but the elongation was lower than that on land. As the proportion of ring laser power increases from 1 / 3 to 2 / 3, the elongation of underwater joint increases by about 50 %.