Abstract: Based on a typical recompression Brayton cycle, a thermodynamic model was established for a supercritical carbon dioxide (sCO₂) power generation cycle, and analyses were conducted on the influence of key parameters on the system performance. Through design optimization by applying genetic algorithm, the maximum efficiency of system and corresponding operation parameters were obtained. Results show that, a higher system cycle efficiency can be obtained when the inlet temperature and pressure of main compressor are close to the critical point and the inlet temperature of turbine is higher. With the increase of the pressure ratio of main compressor, the cycle efficiency increases at first and then decreases, while there is an optimal pressure ratio. Research results can serve as a technical reference for the engineering application of sCO₂ power generation technology.