The invention discloses an overflow-preventing material guide groove of a cement car-loading machine. The overflow-preventing material guide groove of the cement car-loading machine comprises side plates, supporting columns, a base plate, sealing plates, a belt, rotating mechanisms, rolling wheels, clamping devices, rotary mechanisms and a pedestal plate. The base plate is installed between the supporting columns, the supporting columns and the base plate are fixedly connected through nuts, and a top cover is arranged on the tops of the side plates and connected with the side plates in a buckled mode. The side plates are fixedly connected through fixing devices. Pieces of angle steel are installed on the base plate, press parts are fixedly installed on the inner sides of the pieces of angle steel, and the bottoms of the supporting columns are fixedly connected through a connecting plate. According to the overflow-preventing material guide groove of the cement car-loading machine, due to the fact that overflow preventing plates are arranged, the overflow preventing effect is achieved, and the problem of cement leakage of a conventional material guide groove is solved; due to the fact that scraping preventing plates are arranged on the two sides of the belt and are large in contact area, the localized wear of the belt is reduced, and the service life of the belt is prolonged; andthe integral structure is simple, operation is easy, and the problem that material taking, transporting and material scraping operation are difficult is solved.