Building water supply system corrosion and scale prevention device and control method thereof

The invention discloses a building water supply system corrosion and scale prevention device and a control method thereof. The building water supply system corrosion and scale prevention device is arranged on a water supply pipeline between a water meter of a conventional building family splitting water supply system and a domestic water faucet and comprises an air diaphragm tank, a closed air pressure tank, a control unit and multiple valves arranged on the water supply pipeline; the water supply pipeline comprises a main pipeline arranged behind the water meter, a first pipeline enabling themain pipeline to be connected with the closed air pressure tank, a second pipeline enabling the main pipeline to be connected with the air diaphragm tank and a third pipeline enabling the closed airpressure tank to be connected with the air diaphragm tank; and the closed air pressure tank is connected with the domestic water faucet. The control method of the building water supply system corrosion and scale prevention dev