The utility model provides a generating set backheat steady voltage blowpipe system of drawing gas, including the interim system of blowpipe, the interim system of blowpipe receives the steam that the boiler produced, still includes the interim system of drawing gas, the interim system of drawing gas is followed interim pipeline is drawn forth to steam conduit behind the re -heater target plate of the interim system of blowpipe, connects generating set's high pressure feed water heater, and the reheat steam of the re -heater target plate of will flowing through carries to high pressure feed water heater and heats the feedwater of boiler, high pressure feed water heater's steam output is provided with blow -off line. The utility model discloses a sweep steam heating boiler feed water, does not need extra vapour source, therefore total fuel consumption greatly reduced, also greatly reduced the exhaust gas volumn to the heat convection volume has been reduced, so that adjust superheated steam and reheat steam's temperature better.