The utility model provides a special-purpose chassis of the self-dumping truck, comprising an operator cabin, a carriage, a front axle, transmission shafts, front vehicle wheels and back wheels, wherein an engine is installed on the carriage, the engine is connected with a gear box, a storage-battery box, a duplex through drive axle, a steel-plate spring balance suspension device, a drive axle are arranged on the carriage, and the front axle is connected with a steering device, a first lifting oil cylinder lower-support and a second lifting oil cylinder lower-support are respectively arranged on the carriage, a first supporting rack and a second supporting rack are arranged in the back portion of the carriage. The utility model has the advantages that a special-purpose carriage is designed, and the accessory carriage and chassis main carriage are designed to be integral, the lifting oil cylinder lower-support and the back supporting racks are directly arranged on the chassis main carriage, the containers can be directly arranged on the chassis carriage, the center-of-gravity position of the whole vehicle is lowered, and the cost of the whole vehicle is reduced, and the scale, standardization and series production can be done. The utility model further has the advantages of convenient and flexible operation, small turning radius, big load-carrying, good safety, convenient maintenance and the like.