Ventilation system for cross-water-area long-distance comprehensive pipe gallery and ventilation method thereof

The invention provides a ventilation system for a cross-water-area long-distance comprehensive pipe gallery and a ventilation method of the ventilation system. A cross-water-area section of the comprehensive pipe gallery is located between two land area sections. The exhaust shaft and the air supply shaft are arranged on two land sections of the utility tunnel respectively, an exhaust fan is arranged in the exhaust shaft, and an air feeder is arranged in the air supply shaft; an exhaust duct and an air supply duct are arranged at the top of the utility tunnel; the exhaust shaft is communicated with the exhaust duct, and the air supply shaft is communicated with the air supply duct; the comprehensive pipe gallery comprises a plurality of fireproof subareas, an exhaust outlet communicated with each fireproof subarea is formed in a bottom plate or the side wall of the exhaust duct, and an air supply outlet communicated with each fireproof subarea is formed in a bottom plate or the side wall of the air supply duc