The invention provides an auxiliary stinger for field sampling of flue gas. The auxiliary stinger is connected onto a sampling opening of a flue. The auxiliary stinger comprises a sleeve piece, a stinger and at least one sampling pipe clamping piece lock, wherein the sleeve piece is provided with a positioning part; when the sleeve piece sleeves the sampling opening, the positioning part can be used for relatively fixing the sleeve piece and the sampling opening; one end of the stinger is connected with the sleeve piece; when a smoke dust sampling pipe is inserted into the sampling opening, the stinger can be used for supporting the smoke dust sampling pipe; the sampling pipe clamping piece lock sleeves the stinger; when the smoke dust sampling pipe is arranged on the stinger, the sampling pipe clamping piece lock can be used for locking the stinger and the smoke dust sampling pipe together. The auxiliary stinger for the field sampling of the flue gas, provided by the invention can be used for rapidly and conveniently fixing smoke dust sampling pipes with various purposes on the sampling opening, so that the working efficiency of the field sampling of the flue gas is improved and test errors caused by the fact that the smoke dust sampling pipe is not properly mounted are effectively avoided.