The utility model relates to a hot galvannealing stove gas analysis appearance automatic water discharging device belongs to strip production auxiliary assembly technical field. Including drainage tank, drain pipe and blow off pipe, the wash port of gas analysis appearance filter lower part is connected to the drain pipe upper end, and the lower extreme is located below drainage tank's the surfaceof water, blow off pipe one end is passed the drainage tank lateral wall and is located drainage tank, and the other end is said with blowdown main pipe and is connected. The utility model disclosescan automatic exhaust gas analysis appearance filter inside excessive moisture, avoid taking place gas analysis appearance filter clogging or vapor and get into the major loop condition that detects,the drainage process does not influence the sealing ring border and the intraductal gas composition of pipeline, guarantees that the annealing furnace gas detects the accuracy and the zinc -plated production order of data.