Investigation and analysis is carried out on defects detected by non-destructive testing in nuclear stabilizer nozzles welded by hot wire TIG welding,it is analyzed and found out that the main cause of these defects is lack of fusion between beads and layers,and there are some problems in matching of welding parameters and the process control. By considering the appearance of weld and the amount of overlap,the parameters are calculated and matched, like welding current,wire feed rate,etc. to optimize welding technology,which is verified by the technological test. And the results show that adopting the optimized welding parameters and improved process control measures are successfully to solve and avoid similar problems happened again. The improved technology has been applied to products, which improves the qualified rate of non-destructive testing of the hot wire TIG welding and ensures the equipment quality.