The invention relates to an adjustable washroom glass demisting cleaning device. The adjustable washroom glass demisting cleaning device comprises a sucking disc, a fixed seat, a limiting rod, an adjustable fixed rod, a fastening positioning knob, a scraping knife fixing rod, a scraping knife, a spring and a spring fixing seat. In a normal state, the adjustable fixed rod and the limiting rod are in an overlapped state so that the sucking disc is adsorbed to a corner in a glass mirror surface or frame; the scraping knife fixing rod is moved back and forth by a hand; the fastening positioning knob is adjusted and screwed after the scraping knife fixing rod is adjusted according to the size of the mirror surface; after the adjustable fixed rod and the scraping knife fixing rod are fixed in place, the adjustable fixed rod can be wholly pulled away and can be loosened after the adjustable fixed rod and the limiting rod form a certain included angle. The adjustable fixed rod is retracted at a uniform speed under the action of spring stress; a plastic scraping knife positioned in the scraping knife fixing rod is only adhered to the glass mirror surface to wipe the mist on the surface of the glass mirror, so that the purpose of cleaning the glass mirror surface is achieved. The scraping knife can be detached and replaced for continuous use after the scraping knife is aged.