Ni-based high-temperature ally have excellent high temperature mechanical properties and corrosion resista-nce,which are often used in nuclear power equipment. However,recent studies have found that this kind of material has obvious ductility dip cracking tendency,which will lead to the existence of great security risk of the key components in service. Aiming at this problem,this paper selects Inconel 690 welding deposited metal,Using STF method to explore the ductility dip cracking temperature range and high temperature strain threshold value,further reveals themechanism of ductility dip cracking of Ni-based high-temperature ally.