To improve operation efficiency and increase output by using cooling water, LNG cold, cold exhaust and liquid air to make cooling air of a rotor and a blade of a gas turbine low temperature in a low-temperature turbine power generating system having a combination of combined cycle power generating equipment, low- temperature equipment and liquid air power generating equipment.

This combined cycle power generating equipment 1 includes a compressor 2, a gas turbine 4, a combustor 3, and an exhaust heat recovery boiler 5 and the like. This system includes a mixer MX for mixing sucked atmospheric air of the compressor 2 and low-temperature air from a low-temperature equipment 10, including a high-pressure compressor 11, an LNG evaporator 12 and a low-temperature heat exchanger 13, and some of the obtained low-temperature air is supplied to the combustor 3, the residue being subjected to air bleed to be supplied to an air cooler AC1. The bleed air from the power generating equipment 1 is cooled by the LNG evaporator 12 of the low-temperature equipment 10 and then is liquefied by an expansion turbine 16 and a condenser 17. Liquid air is stored in a tank 18. An expansion turbine 25 and a gas turbine 29 are driven by a liquid air power generating equipment 20 to generate power.