In order to increase the recovery and utilization efficiency of regenerative braking energy, this paper explores the energy transfer and distribution strategy of hybrid energy storage system with battery and ultracapacitor. The detailed loss and recovery of energy flow path are analyzed based on the driving/regenerative process of dual supply electric vehicle. Considering the charge-discharge loss of ultracapacitor and battery as well as DC/DC converter loss, a distribution strategy of comprehensive efficiency optimum is proposed for power allocation to maximize energy recovery and utilization efficiency. The quantitative formulas suitable for HESS are deduced to evaluate the regenerative energy recovery rate. Through comparing different power allocation strategies and regenerative braking strategies, it is verified that the proposed allocation strategy can improve the comprehensive energy utilization efficiency of energy storage system.