Abstract: The present disclosure discloses a bus voltage modulation method for a series dynamic reconfiguration battery system, comprising: collecting a voltage value of each battery module, and arranging in a descending order according to magnitudes of the voltage values; selecting a battery module corresponding to the highest voltage value; determining whether the serial number i of the selected battery module is less than a total number N of series battery modules, if a determination result is YES, accumulating voltage values corresponding to the selected battery modules, and determining whether a voltage accumulation value of the battery modules is within a preset range; and repeating the above content until an output bus voltage meets requirements for the preset range. A dynamic reconfiguration battery system based on a software-defined technology of the present disclosure can reconstruct and output a desired bus voltage according to voltages of respective battery modules in real time.