Laser welding has been widely used in many fields as the characteristics of highly concentrated energy, small heat affected zone, small deformation of workpiece, high welding efficiency, good welding quality and high degree of automation. However, it has not been popularized in nuclear power equipment manufacturing. The laser welding technology in this paper is first adopted in domestic similar nuclear power equipment. The welding quality problems in the storage sleeve of the underwater spent fuel storage rack of nuclear power units in the previous project and the welding quality problems in the application of laser welding and their causes are analyzed and summarized. The technical improvement measures are proposed from the aspects of welding parameter optimization, weld deformation control, application of run-on tab and run-off tab,cleanliness control and so on, and good results are obtained,which provides reference experience for the application of laser welding in the storage sleeve of nuclear spent fuel storage rack.