Abstract: The GH4169 alloy joints were obtained in electron beam (EB) welding,and the fracture toughness tests of the joints were carried out on the crack tip opening displacement (CTOD) both at the temperature of 20℃ and 650℃.Based on the CTOD test,crack tolerance of EB-joints was studied.The results show that no matter what temperature it is,normal (20℃) or high (650℃) temperature,the average CTOD value of the materials is higher than that of the joints,and the average CTOD value of the joints is low,easy to be fractured.The result of calculating the crack tolerance shows that under the same stress level,the crack tolerance of the metal is higher than that of the joint,and when the stress level increases,the difference decreases.