In order to effectively utilize the regenerative energy returned by the elevator and reduce the energy loss of the system, this paper focuses on the energy storage characteristics of the ultracapacitor, Firstly, the structure and principle of elevator energy storage system based on supercapacitor are introduced; secondly, the small signal model of bidirectional DC/DC converter is established, and the double closed-loop control structure and parameter design process of bidirectional DC/DC converter based on traditional PI controller are discussed; then, on the basis of analyzing the principle of ant-lion optimization algorithm, a PI parameter design method based on ALO algorithm is proposed. Finally, the simulation model of elevator energy storage system based on ULtracapacitor is established by using MATLAB simulation software. The simulation results show that the ultracapacitor can timely and accurately recover the braking energy and return the recovered energy to the DC bus, ensuring the voltage stability of the DC bus and reducing the energy consumption of the system, which fully verifies the effectiveness and superiority of the method.