Abstract: The power-heat conversion performance of turbine pre-swirl system with the rotor-stator cavity and the rotor-rotor cavity will directly affect the high-temperature thermal protection of the turbine rotor blade. This study focused on theoretical analysis to reveal the correlation mechanism between temperature drop and power consumption. Results indicated that the dimensionless temperature drop and power consumption of the system were strongly correlated with the swirl velocity coefficient, pre-swirl radius ratio, pre-swirl nozzle outlet velocity coefficient, and rotor Mach number. Based on energy conservation, the dimensionless power consumption of the system decreased linearly with the increase of dimensionless temperature drop. Moreover, the higher the temperature drop was, the lower the power consumption was. Under the adiabatic condition, the dimensionless temperature drop and the dimensionless power consumption of the system increased and decreased with the increase of pre-swirl nozzle outlet velocity coefficient and the decrease of the rotor Mach number, respectively. Therefore, the correlation mechanism of temperature drop and power consumption could be applied to effectively evaluate the pre-swirl system performance design for air supply into the turbine rotor blade.