A charging circuit is disclosed. The charging circuit utilizes multi-level technology to improve the efficiency of the charging circuit under the premise of maintaining the boosting, bucking, and bucking-boosting functions of the traditional buck-boost topology. Especially under the circumstance of high input voltage, it can give full play to the advantages of multi levels. The switching loss, withstand voltage requirements of power MOSFTs, and inductance are reduced, and the efficiency is improved.