Abstract: The Allam cycle is a power cycle fueled by natural gas using supercritical carbon dioxide as the working fluid, characterized by extremely high cycle efficiency, a near 100% carbon dioxide capture rate, and the potential for near-zero system emissions. A thermodynamic calculation model of the Allam cycle was developed, and a sensitivity analysis was conducted regarding the impacts of turbine inlet and outlet parameters, turbine cooling gas temperature, isentropic efficiency of power equipment, and the minimum cycle temperature on the system cycle efficiency. Based on the optimization results, a parameter scheme for a 100 MW class Allam cycle was proposed. The results indicate that the influence of turbine inlet pressure, inlet temperature, and outlet pressure on cycle efficiency exhibits a non-monotonic relationship. Effectively utilizing turbine exhaust waste heat and increasing the cooling gas temperature can improve the system cycle efficiency. Among the system power equipment, compared with the influence of compressor isentropic efficiency, turbine isentropic efficiency has a greater impact on the system cycle efficiency, with every 1 percentage point increase in turbine isentropic efficiency resulting in 0.32 percentage points increase in system cycle efficiency. Under the conditions of a turbine inlet pressure of 28 MPa, inlet temperature of 1 150 ℃, outlet pressure of 3.8 MPa, and a minimum cycle temperature of 24 ℃, the system cycle efficiency reaches 54.22%.