The invention discloses a dual-clutch transmission with a special reverse structure and a duplex gear. Particularly, the dual-clutch transmission is provided with seven drive positions, a reverse position, four synchronizers and a duplex gear meshing structure. The dual-clutch transmission has the advantages that the design of special reverse structure is adopted, an idler shaft and accessory gears in the traditional transmission are omitted, the inside structure of the transmission is simplified, production cost is reduced, and the space of the transmission is saved; the design of seven-drive transmission structure is adopted, and an engine is imparted better economy and dynamic performance; arrangement of a seventh drive gear and a reverse gear is more reasonable; each synchronizer acts on two positions at the same time so that the synchronizers are fully utilized; the duplex gear serves for third and fifth positions, the axial distance of the whole transmission is shortened, tooth matching is easier, and selection on axle base and tooth matching is more balanced.