The utility model discloses a secondary combustion chamber, include: section of thick bamboo wall, section of thick bamboo wall centers on the airtight space that forms a vertical setting, be used forwaste liquid spray gun male waste liquid to spout the hand -hole, the waste liquid spout the hand -hole set up in section of thick bamboo wall, just the axis that the waste liquid spouts the hand -hole is along downward to cylinder wall inner side's direction slope outside section of thick bamboo wall. The utility model discloses an it spouts the hand -hole slope downwards to set up the waste liquid to after inserting the waste liquid spray gun, the generation of waste liquid's of burning the flame downwardly extending that can slope, thereby extend with prior art's flame level and compare, from premature ignition to a certain extent the waste liquid, lengthened the dwell time of flue gas more than secondary combustion chamber1100 DEG C under the circumstances that does not increase secondary combustion chamber diameter or height, improved the clearance of dioxin.