A charging control apparatus provides a supply power to first and second mobile devices. Each of the first and the second mobile device includes a mobile charging circuit and a battery. The charging control apparatus includes a switching power converter for converting an input power to the supply power, and a conversion control circuit for controlling the switching power converter according to the following steps: S1: controlling the switching power converter, so as to establish a current versus voltage characteristic curve corresponding to the supply power; and S2: determining a charging mode combinations of the first and the second mobile device and/or adjusting a supply voltage of the supply power to charge the battery of each mobile device according to the current versus voltage characteristic curve, so as to reduce a voltage drop of each mobile device as well as the power loss.