The utility model discloses a flue gas sampling gun that flow equalizes, including inlet collector, the inside cavity that is equipped with of inlet collector, inlet collector's top level is equipped with the main flue gas pipe that feeds through with the cavity, inlet collector's bottom is equipped with two spinal branch tracheas of parallel of each other, the middle part of bronchus is fixed on inlet collector and the cavity intercommunication inside with inlet collector, the bronchus is first bronchus and second bronchus respectively, first bronchus and second bronchus are all parallel with main flue gas pipe, the both ends of first bronchus and second bronchus are equipped with the jack respectively, it has the discharge to peg graft respectively in the jack. The utility model discloses can realize freely adjusting of sampling gun length to realize the use of different capacity boilers, the discharge has multiple length specification, can realize the collection of flue gas according to the different discharges that adopt different specifications of boiler capacity, be equipped with the hole of flow equalizing on the discharge, the pressure in the time of can making the flue gas sample keeps unanimous.