The utility model discloses a sulfur dioxide minimum discharge detection device, characterized by: detection device includes flue gas sampling rifle and flue gas analyzer, and flue gas sampling rifle adopts the ceramic vacuum tubes way, and the ceramic vacuum tubes way is by the outer cover tubular construction that has a vacuum cavity that forms of pyroceram inner tube and ceramic pipe, and sampling rifle head is connected through leading filter to the one end of pyroceram inner tube, and the other end of pyroceram inner tube is through the hose connection flue gas analyzer's that samples flue gas introducing port, set up the hanging structure at flue gas analyzer's back, utilize the hanging structure to hang flue gas analyzer and establish in exhanst gas outlet department. The utility model discloses it is effectual to keep warm, can endure high temperature, and resistant gas corrosion can effectively reduce the gaseous error that the measurement existed of SO2 to low concentration and high humility, improves the accuracy of test result.