Abstract: In order to avoid the sudden power failure of power supply equipment of underground battery locomotive, this can cause serious problems to the underground work. A new type of bidirectional non-isolated DC converter is designed. The circuit structure adopts the topological structure of quasi-Z source, the two-way transmission power and working process of the DC converter are deeply analyzed, and the voltage gain is derived by using the volt-second balance principle. The experimental results and MATLAB/Simulink simulation show that the DC converter can realize the bidirectional transmission of power and has the advantages of high capacity of boosting, high power conversion efficiency and low cost compared with the traditional bidirectional DC converter.