This paper introduces the TIG welding process of duplex stainless steel 2205 under the type of 1.2 mm thin plate end joint. Starting from the characteristics and appli-cation of 2205,the weldability of materials,welding process parameters and operation essentials,it emphatically analyzes the problems(uneven metallographic structure) that are easy to occur in the process of thin plate end welding,and the relevant process measures and measures to solve the defects.