The utility model discloses a flue gas sampling device, visit pipe, the sampling cavity body, sampling filter, heating device, blowback unit including the sampling, sampling spy pipe sets up the front end at flue gas sampling device, and in the flue was inserted to one end, the other end communicate with the sampling cavity body for it is internal to collect sampling cavity with the sample gas, heating device includes heating rod and heating sheath, the heating rod sets up internally at sampling cavity, heats heat preservation to sampling cavity is internal, the outside of tubes is visited in the sampling of being connected with the flue to the setting of heating sheath, visits the pipe to the sampling and heats heat preservation, prevents flue gas condensation before getting into the sampling cavity body, the setting of sampling filter is internal at sampling cavity, carries out the smoke and dust to the sample gas and filters, prevents that the dust from getting into inside the analytic system, the blowback unit is regularly visited to manage to the sampling and is carried out the blowback with the sampling filter, prevents that the smoke and dust from blockking up sampling spy pipe, the sampling filter leads to flue gas sampling gas circuit to be blockked up.