Hot deformation characteristics of a new-type Ni-Cr-Co based alloy was investigated by isothermal compression tests under the deformation temperature range of 1050~1250 ℃ and strain rate range of 0.001~1 s_^-1. The electron backscatter diffraction (EBSD) technique was employed to investiage the microstructure evolution and nucleation mechanisms of dynamic recrystallization. The result showed that the flow stress decreases with the increasing of deformation temperature and the decreasing of strain rate. The Arrhenius constitutive equation and processing map were established based on the hot deformation data, and the hot deformation activation energy was calculated as 520.03 kJ/mol. The optimum hot working conditions were obtained in the temperature scope of 1175~1250 ℃ and the strain rate range of 0.006~1 s_^-1 with the peak power dissipation efficiency of 45%. The fraction of dynamic recrystallization increases with the increasing of deformation temperature and the decreasing of strain rate. And during dynamic recrystallization, a large number of deformed grains were replaced by fine dynamic recrystallized grains and a high frequency of ∑3 twin boundaries were generated. The dominant dynamic recrystallization nucleation mechanism is grain boundary bulging, which is a typical feature of discontinuous dynamic recrystallization. In the low temperature and high strain rate region, continuous dynamic recrystallization characterized by the rotation of subgrains was detected. However, continuous dynamic recrystallization was just an assistant nucleation mechanism for the alloy.