To ensure efficient energy charging process inside energy storage system, dual-active-bridge (DAB) becomes significant interface circuit because of its bidirectional power transmission ability and simple modulation scheme. In order to achieve DAB efficiency promotion, lower root-mean-square (RMS) current stress and wider soft-switching region are required. Therefore, a multiple duty modulation (MDM) is proposed to achieve aforementioned goals. In this article, detailed derivations of mathematical models for typical MDM modes are demonstrated. Power characteristics and soft-switching performance are also depicted in detailed. RMS current is selected as optimization objective which is implemented by fmincon function in MATLAB. To substantiate the effectiveness of the proposed modulation scheme, a comprehensive comparison among existing works in terms of RMS current and soft-switching region are implemented under different conditions. Finally, a DAB-based experimental prototype is built and effectiveness under proposed modulation scheme is verified.