Configuration design of super capacitor energy storage device only according to the capacity and power constraints, without considering super capacitors constraints of maximum current situation, will seriously affect the service life of a super capacitor storage device. Super capacitors theory and optimizing allocation for vehicle braking energy recovery of urban rail transit vehicle were researched. Considering the two aspects of power and capacity, combining the maximum current of super capacitor optimal constraint, through theoretical analysis of the super capacitor energy storage configuration method, the optimal capacitance capacitor device configuration, the optimal depth of discharge dopt and the optimal max current Isc, max were concluded. Through Matlab simulation, the optimal configuration of super capacitor energy storage device of Nanjing metro line 1 vehicles was determined, as well as the optimal maximum current Ic, max of the control process, which would provide certain guiding significance to design of on-board capacitor energy storage system.