The invention provides a cleaning method of a tunnel cleaning machine. A cleaning vehicle comprises a vehicle frame, a cleaning mechanism, a recovery device and a movement device, wherein the cleaningmechanism comprises a cleaning device, an air compression mechanism and a liquid state carbon dioxide storage tank, and the cleaning device is independently connected with the recovery device, the air compression mechanism and the liquid state carbon dioxide storage tank. The height of each first wheel is regulated, so that the first wheels of the cleaning machine are on a road surface, second wheels are on road shoulders to reduce road occupation and lower a traffic accident risk, dirt generated after a tunnel is cleaned and carbon dioxide formed after dry ice is gasified are subjected to instant recovery through a negative pressure principle, a secondary operation is reduced, so that work cost is lowered, in addition, tunnel cleaning and recovery substance absorption are simultaneouslycarried out, working efficiency is high, and operation cost is lowered.