The invention discloses a liftable self-propelled continuous pushing system for a large-span steel box beam. The liftable self-propelled continuous pushing system for the large-span steel box beam comprises a automatically-positioning continuous pushing device, an automatic pier top slideway elevation adjusting device and a horizontal limiting and correcting device. By virtue of a highly automated control system, precise positioning and synchronous pushing are achieved, damage to the quality of a steel box structure is minimized, and a relatively good quality control effect is ensured. The invention further discloses a pushing construction method. Through arrangement of the automatically-positioning continuous pushing device and the automatic pier top slideway elevation adjusting device in a pushing construction technology, self-propelled advancement and precise positioning of the pushing device are achieved, lifting and mounting and dismounting operation procedures of mechanical equipment are saved, the operation of the construction technology is simplified, the technical difficulty is reduced, the on-site controllability is substantially improved, the construction time is shortened, the safety risks are reduced, and popularization and application are easy.