Influence of coolant injection on the aerodynamic performance of high pressure turbine and secondary flow structure in cascade channel were numerically simulated. The results indicate that cooling high-pressure turbine vane and rotor load decreased

vane inlet and outlet Mach number decreased

rotor outlet relative Mach number increased in the radial region from 0 to 0.55

but decreased in the radial region from 0.55 to 1.0 with the increase of cooling air mass flow. Vane inlet and outlet flow angle was less affected by cooling air mass flow change. Cooling air mass flow increased from 4.83% to 14.49% of compressor inlet mass flow

rotor inlet relative flow angle increased in the radial region from 0.05 to 0.95

but outlet relative flow angle decreased in the radial region from 0.6 to 1.0; adiabatic wall cooling efficiency of vane first increased and then decreased while adiabatic wall cooling efficiency of rotor gradually improved by 19.33%. Hub and case sealing gas entered into the rotor cascade channel in bundles

with cavity sealing gas flow was greater affected by the pump effect of rotating wall.