Abstract: As the long dwell time of high temperature and slow cooling rate in phase transformati-on during high heat input welding, the austenite grain rapidly grew in heat affected zone. Using techniques such as TiN、Ti-B to inhibit austenite grain growth for improving the high heat input welding performance is difficult to meet the requirements of higher welding line energy. Oxide metallurgy technology has the vital significance for improving welding property of the heat affected zone. This paper mainly describes the method and development direction for improving toughness and focus on analysising and forecasting of the possibility for Y applys to improve toughness of the heat affected zone.