An exhaust gas post-processing system according to an embodiment of the present invention includes: an exhaust flow path for moving an exhaust gas discharged from an engine; at least one aftertreatment device installed on the exhaust flow path and purifying the exhaust gas; a burner installed on the exhaust flow path and heating the exhaust gas upstream of the at least one aftertreatment device; a fuel supplier for supplying a fuel to the burner; and an air supply flow path for supplying an air to the burner. The air supply flow path supplies a part of the exhaust gas discharged from the engine as the air to the burner.