Abstract: Similar structures in the heat affected zone of 10Ni8CrMoV steel are obtained using a thermal simulation tester, and the dynamic mechanical behavior of the heat affected zone specimens are characterized by the Hopkinson Bar, and its microstructure are observed. The results show that under the high strain rate, the real stress of the heat affected zone increases with the increase of strain rate, showing obvious strain rate strengthening effect. At a strain rate of 2 000 s^-1, a large number of deformed twins appear in the specimen, and the specimen is sheared at a strain rate of 4 000 s^-1. Based on the Johnson-Cook model, a dynamic constitutive model of the heat affected zone of 10Ni8CrMoV steel is obtained.