The invention relates to an equipment maintaining device and system as well as an equipment maintaining method. The equipment maintaining device comprises a framework, a maintaining part and supporting parts, wherein the framework comprises a first end part and a second end part which are opposite, an accommodating space which extends to the second end part from the first end part, and an opening which extends to the second end part from the first end part; the opening communicates with the accommodating space; the maintaining part is arranged on the framework; the maintaining part is opposite to a to-be-maintained area of the outer surface of equipment; the supporting parts are arranged on the inner wall, surrounding the accommodating space, of the framework; the supporting parts are arranged on areas, at the two sides of the opening, of the inner wall; each supporting part comprises a resisting part and a drive part, wherein the drive part is arranged between the resisting part and the inner wall, the drive part can drive the resisting part to get close to or get away from the inner wall; a clamping hole is formed between the resisting parts at the two sides of the opening; and the clamping hole corresponds to the opening. According to the embodiment of the invention, the equipment maintaining device is high in maintaining working efficiency, is low in labor intensity of a maintaining process, and is safe.