The stress-strain curves of GH4742 at deformation temperature of 980-1100 °C and strain rate of 5×10_^-3 s-1 to 5 s_^-1 were acquired through single-pass isothermal compression experiments. The flow stress, critical strain capacity and structure evolution dynamics of GH4742 during dynamic recrystallization were systematically described on basis of experimental data using KM model, Poliak-Jonas criterion, and Avrami model. Then based on the Prasad power dissipation rate model, the structural transformation volume fraction was introduced to determine the energy variation rules during dynamic recrystallization. The mechanism underlying the dynamic recrystallization of GH4742 was revealed with the help of microstructure characterization. It was found the critical strain capacity of GH4742 during dynamic recrystallization decreased and the structural transformation volume fraction increased with the rise of deformation temperature or the decline of strain rate. The power dissipation rate of complete dynamic recrystallization was larger than 0.44, and the forming mechanism was dislocation-induced continuous dynamic recrystallization.