The invention relates to an intelligent cleaning device for a motor car rail. The intelligent cleaning device comprises a cleaning supporting plate. One cleaning adjusting branched chain and one high-pressure cleaning branched chain are mounted on one of two sides of the lower end surface of the cleaning supporting plate. The cleaning adjusting branched chain and the high-pressure cleaning branched chain, which are arranged on one side of the cleaning supporting plate, are symmetrical to those, which are arranged on the other side of the cleaning supporting plate. The two cleaning adjusting branched chains are respectively connected with the two high-pressure cleaning branched chains. The two cleaning adjusting branched chains can be used for accurately adjusting the high-pressure cleaning angles of the two high-pressure cleaning branched chains. After the motor car rail is polished, the two high-pressure cleaning branched chains are adjusted by the two cleaning adjusting branched chains to move downwards, and residual scrap iron generated after polishing and non-cleaned dust, which are attached to the motor car rail, are quickly cleaned by a high-pressure water jet working principle, and the high-pressure cleaning effect is good; each cleaning adjusting branched chain comprises two cleaning lifting lugs welded on the lower end surface of the cleaning supporting plate, an adjusting shaft is mounted between the cleaning lifting lugs, an adjusting gear is mounted in the middle of the adjusting shaft through a key, and an adjusting motor is mounted at the rear end of the adjusting shaft through a coupling. The intelligent cleaning device can realize a full-automatic cleaning function after the motor car rail is polished, manual operation is not required, and the degree of automation is high.