The invention discloses a high-temperature heating boiler system with a power generating function and an operating method thereof. A tubular boiler is connected with a high-pressure steam-water separator through a high-pressure steam pipe. The high-pressure steam-water separator is connected with a jet pump through a throttle valve and a concentrated heat-liquid supplying pipe. The jet pump is connected with a steam-water mixing condenser. A boiler flue gas pipe of the tubular boiler is connected with a medium-temperature flue gas pipe through a flue gas steam superheater. The medium-temperature flue gas pipe is connected with a flue gas regenerator which is connected with a heat supply water return pipe, a preheating water return pipe and a flue gas exhaust pipe. The preheating water return pipe is connected with the jet pump through a jet flow drainage pipe. The high-pressure steam-water separator is further connected with the flue gas steam superheater through a steam superheating air inlet pipe. The flue gas steam superheater is connected with a steam turbine through a working steam pipe. The steam turbine is connected with a generator and a steam exhaust pipe. The steam exhaust pipe is connected with the steam-water mixing condenser. According to the high-temperature heating boiler system with the power generating function and the operating method thereof, phase change expansion caused by heating is made full use of, and high-grade energy sources are preferentially output and comprehensively and efficiently utilized.