Breathing filtering device of water tank

The utility model belongs to the technical field of water tank accessories, and particularly relates to a water tank breathing filtering device which comprises a connecting module, a first connector, a second connector and a breathing filtering module. The expiration module is connected with the second connector of the connecting module through a first gas conveying pipe so as to decompose undissolved ozone gas in the water tank and discharge the ozone gas out of the water tank; the gas suction module is connected with the third connector of the connecting module through a second gas conveying pipe so as to inject the filtered clean gas into the water tank; wherein the expiration module and the inspiration module are respectively communicated with the connecting module to form an expiration passage and an inspiration passage which are separated and independent, and through separation and independent'expiration 'and'inspiration', not only is the cleanliness of gas ensured, but also ozone is decomposed in time,