The invention discloses a visual dismantling-free three-way catalyst cleaning method and device, and belongs to the cleaning and maintaining field of automobile parts. A cleaning agent nozzle of the cleaning device and an endoscope are integrally mounted, only an automobile front oxygen sensor needs to be dismantled before cleaning, a visual micro-cleaning device can be probed in from a front oxygen sensor hole in the cleaning process, so that an inner image of a three-way catalyst is accurately obtained, the blocking degree of a catalyst carrier can be observed through a computer display, accordingly, an air compressor and a valve are adjusted to control the injection pressure of a cleaning agent and the dosage of the cleaning agent, the best cleaning effect is achieved, and the dosage of the cleaning agent is saved. The visual dismantling-free three-way catalyst cleaning method and device have the advantages that the endoscope is used for obtaining the image, the computer display is used for displaying the image, the blocking degree of the catalyst carrier is judged, the dosage of the cleaning agent can be controlled, and the cleaning effect is judged; by the adoption of the method, when the three-way catalyst is cleaned, idling of an engine is of no need, the three-way catalyst does not need to be dismantled, visual dismantling-free cleaning is achieved, and thus cleaning quality and benefits are improved.