Hot compression test was carried out at 1000℃ to investigate the dynamic recrystallization nucleation mechanism of a nickel-base superalloy. It was found that the bulging of original grain boundaries was inhibited by carbides and deformation twins at the boundaries. Recrystallized nuclei evolved from the subgrains of dislocation reconfiguration along original grain boundaries, and the growth of the potential nuclei was carried out by the coalescence of subgrains. The necklace structure of recrystallized grains along original grain boundaries was attributed to the strain gradient from grain boundary to grain interior. Hot compression test was carried out at 1000 ℃ to investigate the dynamic recrystallization nucleation mechanism of a nickel-base superalloy. It was found that the bulging of original grain boundaries was inhibited by carbides and deformation twins at the boundaries. Recrystallized nuclei evolved from the subgrains of dislocation reconfiguration along original grain boundaries, and the growth of the potential nuclei was carried out by the coalescence of subgrains. The necklace structure of recrystallized grains along at original grain boundaries at attributed to the strain gradient from grain boundary to grain interior.