The invention relates to the field of thermal power generation and discloses a thermal power generation system. The thermal power generation system comprises a boiler, a coal supply unit, a drying part, a coal mill, a pulverized coal separator, a dehumidifying unit, a flue gas mixing unit and a flue gas processing unit and is characterized in that the drying part is communicated with the coal supply unit, the coal mill is communicated with the drying part, and the pulverized coal separator is communicated with the coal mill; the pulverized coal separator is used for separating pulverized coaland exhaust gas, and the pulverized coal separated by the pulverized coal separator can be directly used for combustion; the flue gas mixing unit is communicated with the smoke discharge outlet of a boiler and used for providing a drying agent for the drying part; a heat exchanging pipeline is arranged in the dehumidifying unit, the exhaust gas separated by the pulverized coal separator enters thedehumidifying unit and is subjected to heat exchange and dehumidifying, and the exhaust gas outlet of the dehumidifying unit is communicated with the flue gas processing unit and the flue gas mixingunit. By the arrangement, the thermal power generation system has the advantages that brown coal high in water content is dewatered to a large extent before combustion, and accordingly boiler efficiency is increased.