Abstract: In order to investigate the impact of key parameters on the thermodynamic performance of both the overall and critical components of a hydrogen-blended heavy-duty gas turbine, a thermodynamic performance calculation model was established, and the definitions and settings of the key parameters in the moldel were explained. By examining different hydrogen blending ratios, turbine inlet temperatures, compressor pressure ratios, and cooling air volumes, the study assessed their influences on the power output and thermal efficiency of gas turbine. Additionally, changes in turbine aerodynamic parameters under different hydrogen blending ratios were analyzed, and the mechanisms behind the impact of hydrogen blending on gas turbine performance were further revealed. The results show that the mixing ratio of hydrogen, turbine inlet temperature, pressure ratio and cooling air quantity are the key parameters that affect the performance of heavy duty hydrogen blended gas turbine; and the changes in aerodynamic parameters of the turbine such as turbine flow angle and outlet Mach number caused by the hydrogen blending ratio changing will affect the aerodynamic performance of the turbine and the thermodynamic performance of the gas turbine.