The performance of nuclear island P265GH steel lining submerged arc welding（SAW） welding joint was studied on chemical composition,microstructure and mechanical properties. The results show that the double-sided SAW with low heat input for steel lining plate is stable,and the welded joint performance meets the specification requirements,demonstr-ating the feasibility of the double-sided SAW with low heat input. In view of the construction experience of steel lining prefabrication assembly, the matters needing attention in the SAW construction of steel lining plate are put forward, which provides a reference for the quality control of subsequent nuclear island steel lining assembly construction.