A charging method for a battery set with a plurality of battery cells, having steps of performing a serial charging on the battery cells; determining whether one of the battery cells reaches a saturation voltage; and performing a uniform separately charging on the battery cells when one of the battery cells reaches the saturation voltage, wherein the uniform separately charging comprises sorting the battery cells according to cell voltages of the battery cells; and sequentially and separately charging the sorted battery cells to a Nth segmented voltage in a Nth segmentation, wherein N is a positive integer from 1 to K, and K is a positive integer larger than 1. The charging method of the present disclosure can reduce the temperature rising of the battery cell due to the longtime charging.