The invention discloses a multi-power-section charging method based on optimum efficiency. According to the multi-power-section charging method, multiple charging piles are included; each charging pile is provided with an AC-DC converter, a communication apparatus and a controller; the adjacent charging piles are connected through a connecting apparatus; the multi-power-section charging method comprises the steps as follows: each controller calculates input power, output power and power loss of each AC-DC converter at intervals of setting time; each controller fits a loss function between power loss and output power according to the power loss obtained by calculation; the adjacent controllers of a set number send respective loss functions to a certain one controller which is used as a main controller to perform optimization and calculation so as to work out the optimal charging power of each charging pile and to send the optimal charging power to the corresponding controller; and the adjacent charging piles are electrically connected through the connecting apparatus, and charging is performed according to the received optimal charging power. By virtue of the multi-power-section charging method, charging tasks of different power requirement can be completed by the charging piles, and meanwhile, the minimum of electric power loss in the charging process can be ensured.