Abstract: A topology structure of a power battery pack for a diesel-electric hybrid locomotive includes a plurality of components. A chopper unit is connected in parallel to a support capacitor, an AC/DC module, a DC/AC module, a reactor unit and a power battery system. The power battery system includes several groups of power modules. The power module includes a contactor unit, a current sensor, a fuse, a power battery, and a voltage sensor. The contactor unit, the current sensor and the power battery are connected in series. Two ends of the voltage sensor are respectively disposed at two ends of the power battery. A locomotive microcomputer is connected to a DUC controller and a power battery management system. The DUC controller is connected to the DC/AC module, the chopper unit and the contactor unit. The power battery management system is connected to the contactor unit.