To address the problem that conventional negative sequence inverse time overcurrent protection for generators cannot accurately characterize the protection’s action time after sudden changes in negative sequence current, a correction approach for the negative sequence inverse time overcurrent protection curve based on the dynamic thermal energy model is proposed. First, the generator terminal negative sequence suppression strategy under new energy control and the variation of negative sequence current during unbalanced transmission line operation are analyzed. A negative sequence inverse time overcurrent protection action scheme is proposed to address the three-stage changes of negative sequence current. Then, a dynamic thermal energy model reflecting the rotor temperature is established based on the real-time measurement of negative sequence current, considering the non-periodic component heat generation and convective radiation heat dissipation. Finally, the model is incorporated into the negative sequence inverse time overcurrent protection, where steady-state temperatures of stator and rotor along with preset negative sequence current are used to characterize the negative sequence inverse time overcurrent protection curve. A correction scheme for the protection curve is further proposed that adjusts the curve based on rotor temperature estimated from real-time negative sequence current inputs. Simulation results show that the constructed dynamic thermal energy model can accurately capture rotor temperature, and the proposed curve characterization and correction scheme achieves high accuracy and strong adaptability.