The present invention provides an UV cleaning device of a glass substrate, comprising a lamp box, an UV lamp positioned above inside the lamp box, a transparent shield positioned under the UV lamp, a humidifier positioned under the transparent shield and a power exhaust device under the transparent shield and opposite to the humidifier; in usage, the glass substrate is conveyed to be inside the lamp box, and UV light generated by the UV lamp irradiates on the glass substrate through the shield to clean the glass substrate and a humidity and an oxygen content inside the lamp box are adjusted with the humidifier to make a surface of the glass substrate adsorb one layer of water molecules. The electrons generated as the UV light cleans can be gradually conducted and led out with water molecules to effectively restrain the accumulation of the electrostatic to reduce the phenomenon of electrostatic damage, and meanwhile, the increase of the oxygen content makes the concentration of the activated oxygen atoms increases along with. Accordingly, the result of cleaning the organic objects with the UV light is promoted.