An AC-DC type uninterruptible power supply includes a rectifying unit, a battery control unit and a switching unit, wherein the rectifying unit is used for rectifying an AC from a power network and outputting a DC; a battery is controlled by the battery control unit to be charged or discharged and outputs a DC during interruption of the AC from the power network; and the switching unit is used for selectively outputting the DC from the rectifying unit or the DC from the battery. Inversion of the UPS and double rectification of a load are omitted.