Parabolic trough concentrating (PTC) solar power generation is the most technologically mature way of solar thermal power generation, which has been developed to industrial and commercial scale. For the current PTC solar thermal power plants, air cooling and recirculation evaporation wet cooling are recognised as common cooling methods. However, evaporation wet cooling brings serious evaporation loss and high water consumption, and air cooling reduces the thermal efficiency of the PTC, both due to the hot and dry climate. Herein, a new cooling system, radiation cooling, was proposed for the PTC thermal power plant which could dissipate the waste heat to the colder universe instead of the surface atmosphere based on radiative heat transfer mode without the requirement of water. The mirror of the PTC has high solar reflectivity and thermal emissivity and is required to reflect sunlight to the collector tube during the day for heat collection and release heat to the cold universe at night during power generation using radiative cooling. A theoretical model that combined the processes of concentration, heat collection, power generation, and cooling of the system was proposed and the predicted results showed that radiative cooling could provide almost all the cooling capacity required for power generation at night, and greatly reduce the cooling water needed for power plant cooling, which provided a possible solution to the water problem of power plants in torrid-arid areas and curb global warming in large-scale application.