Through the analysis for the necessity of onboard energy storage system for urban transit vehicle braking, the rationality of using the super capacitor type energy storage device was put forward. By establishing the model of onboard energy storage system for urban rail transit vehicle braking, and introducing the working principle of braking energy storage system, the selection of main components parameters, including the selection of the super capacitor voltage range, super capacitor capacity, super capacitor determination of the quantity and the inductance was analyzed respectively. Through simulation calculation of the size of the regenerative braking energy, optimal initial charging voltage was determinated based on power-capacity constraint, then the super capacitor array optimization configuration was completed, which provided analysis basis for the overall structure of the energy storage system design and selection of inductance and capacitance.