Abstract: DC/DC converters in electric vehicle charging pile circuits need to have the function of bi-directional transmission of electric energy, and the use of bi-directional active full-bridge (DAB) DC/DC converter in automobile charging piles is susceptible to the problem of unstable output voltage due to the input voltage instability and the sudden change of load. In this paper, we establish a step-down model of DAB converter based on the single phase-shift modulation method, and design a voltage control strategy based on double-integral sliding mode control, which adopts hyperbolic tangent function to reduce the jitter phenomenon of sliding mode control. The simulation comparison and analysis with the traditional PI controller show that the DAB converter based on double-integral sliding mode control has the advantages of strong ability to adapt to load changes and high voltage stability.