In this paper, one-side welding procedure of Q345R/316 L clad plate with 13+3 mm thickness produced in Shougang was studied. The welding sequence was a three-step process,including stainless steel layer welding,transition layer welding and carbon layer welding. The performance of welded joint was analyzed by using tensile test,impact test,bending test and hardness test. The results show that the mechanical property and intergranular corrosion resistance meet the requirements of the relevant technical standards and demands of the users. In addition,the dilution effect of stainless steel layer welding on carbon layer welding in the weld zone of the joint is studied. The first carbon layer welding is suffered the impact of stainless steel,its hardness raises sharply,the hardness and chemical composition of the carbon layer welding are not affected until the fourth carbon layer welding.