The utility model relates to a boiler flue gas heat is recycle device again, wherein, the boiler comprises water tank and heating device, one side of boiler is equipped with the export of discharging fume, export and the air heater of discharging fume connects, one side of air heater is equipped with exhaust duct, exhaust duct and heating device connect, air heater's opposite side and heat exchanger pass through the pipe connection, be equipped with a plurality of flue gases circulation tube bank in the heat exchanger, heat exchanger with advance water piping connection, the other end and the water storage tank connection of inlet tube, the water storage box is equipped with the heat preservation outward, water storage box built -in controller, water storage box and play water piping connection, be equipped with the ball valve in the outlet pipe, the other end and the water tank of outlet pipe are connected, be equipped with level switch in the water tank, one side of heat exchanger is equipped with exhaust pipe, be equipped with dust collector in the exhaust pipe, exhaust pipe connects with the chimney of discharging fume. The utility model provides high energy utilization is rateed, has reduced the granule in discharge flue -gas temperature and the flue gas, has reduced air pollution.