A Kalina cycle power system was developed. The net power output, net power output per ton of geofluid, energy efficiency, and heat exchanger area of per net power were determined as the performance criteria of the power system. The influences of ammonia water mass fraction, solution circulation ratio, geofluid temperature, cooling water temperature, and the heat exchanger end temperature difference on performance criteria were analyzed. Results showed that the performance could be changed by adjusting ammonia water mass fraction. The optimal solution circulation ratio value was about 4 and the corresponding ammonia water mass fraction difference was about 12%~13%. The net power output per ton of geofluid increases and energy efficiency decreased by increasing the heat exchanger end temperature difference.