The invention discloses a crawling ladder system of vehicles. The crawling ladder system comprises a rear baffle component, a retractable ladder device and a connecting device; the rear baffle component comprises an inner wall, an outer wall and a cavity between the inner wall and the outer wall; the retractable ladder device comprises a pair of parallel fine and long components and a plurality oftransverse components, and the transverse components are perpendicular to the fine and long components; the fine and long components comprise first parts with first external dimensions and first cavity dimensions, and second parts with second external dimensions and second cavity dimensions and adjacent to the first parts, and the second external dimensions are smaller than the first cavity dimensions; and the connecting device is used for detachably fixing the retractable ladder device into the cavity of the rear baffle component. Thus, the small automobiles or the motorcycles or the like can enter and exit mainly through simple rod piece combinations, the result is simple, and using is convenient.