Thin-walled stainless steel pipes are widely used in auxiliary systems of nuclear power stations. They are important items in nuclear power welding in service,and their welding quality affects the operation quality of nuclear power plants.This paper mainly introduces the welding technology characteristics and difficulties of thin-walled stainless steel pipes with large diameter in nuclear power stations. It is emphasized that the welding quality of large diameter stainless steel thin-walled pipe can be ensured by the selection of argon chamber,the validation of effect,the use of appropriate pipe group,the adoption of appropriate welding methods and process parameters,and the key point validation in the welding process. This method has been applied in many nuclear power stations in Guangdong Nuclear Power Group of China and has good applicability.