A method and device for estimating remaining available energy of a power battery is provided. The method includes: estimating, under current state, maximum available energy of a first cell with minimum State of Charge (SOC), and maximum available energy of a second cell with minimum of maximum available capability in the power battery; estimating remaining available energy of the first cell based on its maximum available energy and SOC, and estimating remaining available energy of the second cell based on its maximum available energy and SOC; and estimating the remaining available energy of the power battery based on the number of cells included in the power battery and the smaller one of the remaining available energy between the first and the second cell.