The invention relates to the field of thermal power generation and discloses a thermal power generation system which comprises a boiler, a pulverized coal burner, a coal supply unit, a drying part, acoal mill, a pulverized coal separator, a dehumidification unit and a flue gas mixing unit, wherein the pulverized coal separator is used for separating pulverized coal from exhaust gas; the flue gasmixing unit communicates with the smoke vent of the boiler; a heat exchanging pipeline is arranged in the dehumidification unit; the exhaust gas separated out of the pulverized coal separator enters the dehumidification unit for heat exchange dehumidification; part of exhaust gas discharged out of the dehumidification unit enters the flue gas mixing unit to be mixed with furnace smoke and serve asa drying agent to enter the drying part; and the other part of the exhaust gas serves as primary air to feed the pulverized coal separated by the pulverized coal separator into the pulverized coal burner. According to the thermal power generation system, exhaust gas circulates in the system, has the pulverized coal conveying function and also plays the role of low temperature furnace smoke, and emission of the exhaust gas is reduced; in addition, moisture in brown coal does not enter a furnace hearth, so that the fuel combustion efficiency is improved, the boiler heated area is reduced, and the initial investment of the boiler and an auxiliary system is reduced.