Automatic deionized water supply device for test system and working method of automatic deionized water supply device

The invention discloses an automatic deionized water supply device for a test system, which comprises a pretreatment system, an RO system, a membrane deoxidation system, a nitrogen sealing system and a conveying system, the pretreatment system is connected with a water supply port through a water inlet pipeline, the water inlet pipeline is connected with a first dosing device, and the water inlet pipeline is provided with a source water pump; bacteria, inorganic salts, organic matters and viruses in source water are removed through the pretreatment system, and primary purified water is obtained; introducing the primary purified water into an RO (Reverse Osmosis) system through a pipeline, and removing most soluble salts, a small amount of colloids and organic matters in the primary purified water through the RO system to obtain tertiary purified water; introducing the third-stage purified water into a membrane deoxidation system to generate finished product water; the membrane deoxidation system is connected