The utility model discloses a vent pipe. The vent pipe is mainly composed of an elbow section and a straight pipe section, the elbow section is communicated with the straight pipe section through a breathing valve, the elbow section is provided with a filter screen, and a flame arrester is arranged at the middle of the straight pipe section. The vent pipe is capable of preventing the harmful gas explosion and preventing winged insect, dust or vector entering a pool or a well so that the safe running of the gas in the pool or well is guaranteed.