This paper introduces the typical defects and causes of the sealing lip weld for nuclear-grade stainless steel valve,analyzes the failure of important repair processes that affect the welding quality. It has developed the key technical points of the repair and quality control for the valve sealing lip weld,including sealing lip weld cutting,mating surface grinding,component cleaning and inspection,valve body cap assembly,welding and post-weld inspection etc. It also proposed the follow-up improvement direction of the repair for the valve sealing lip weld on the nuclear power site.