The present invention relates to a coal-fired boiler flue gas-catalytic regeneration flue gas combined discharging system, which comprises a catalytic regeneration flue gas unit, a coal-fired boiler flue gas unit and a flue gas desulfurization device, wherein the flue gas desulfurization device is provided with a chimney, the catalytic regeneration flue gas unit comprises a catalytic flue gas waste heat boiler, a catalytic flue gas dust collector and a catalytic economizer, the catalytic flue gas waste heat boiler is connected to the catalytic economizer through the catalytic flue gas dust collector, the coal-fired boiler flue gas unit comprises a steam boiler, a steam superheater, a high temperature economizer, a No.1 high temperature pre-heater, a No.2 high temperature pre-heater, a boiler flue gas low temperature economizer, a No.1 low temperature pre-heater, a denitrification device, No.2 low temperature pre-heater boiler, a boiler flue gas dust collector and an induced fan, the steam boiler, the steam superheater, the high temperature economizer, the No.1 high temperature pre-heater, the No.2 high temperature pre-heater, the boiler flue gas low temperature economizer, the No.1 low temperature pre-heater, the denitrification device, the No.2 low temperature pre-heater boiler, the boiler flue gas dust collector and the induced fan are sequentially connected, and the outlets of the catalytic economizer and the induced fan are connected to the flue gas desulfurization device. According to the present invention, the flue gas emission meets the emission standard so as to reduce the air pollution, protect the natural environment, beneficially optimize the resource allocation, reduce the production apparatus occupation area, and reduce the production cost of the enterprise.