It is very important for the sustainable development of economy and society to exploit new energy and save energy. The global liquefied natural gas (LNG) trade has increased rapidly during recent years because of its steady price. A significant amount of energy is consumed to produce super-cooling LNG about -162 °C in 0.1MPa for the convenience of shipping, which has plenty of cryogenic energy. The cold energy of LNG is generally wasted when the LNG is extracted for utilization. Therefore, utilization of the cold energy of LNG is quite important at the stage of crude oil price increasing. The feasibility of using a combined power cycle to recover cold energy of LNG is analyzed in this present paper. The combined power cycle consists of three parts: fuel combustion system of compressed natural gas (CNG) drawn from natural gas after expanding through natural gas turbine, ammonia-water (AW) Rankine cycle and LNG cold energy cycle. Fuel and air rates, turbine inlet temperature and pressure, ammonia-water condensed temperature, and overall conductance of the heat exchange are considered as key parameters for given LNG flow rate and natural gas transport parameter in the combined power cycle. The present model could be applied to calculate thermal and exergy efficiencies of the combined power cycle according to different calculation parameters and to get optimum conditions of the key parameters for performance improvement of the combined cycle.