In order to solve the adverse effects of distributed power output power fluctuation, load sudden change and uncertain external interference on the bus voltage in DC microgrid, this paper combines the advantages of intelligent PI controller and automatic disturbance rejection controller (ADRC) to design an intelligent automatic disturbance rejection controller (IADRC), which effectively enhances the robustness of the system. In addition, in order to improve the estimation accuracy of the system for disturbance and reduce the estimation error of the traditional linear expansion state observer, an improved linear automatic disturbance rejection control (ILADRC) strategy is proposed, which realizes the accurate reconstruction of the disturbance state by constructing a cascaded linear expansion state observer (LESO) to process the steady-state offset in the disturbance estimation error. Finally, Matlab/Simulink software is used to simulate and compare with conventional PI controllers and conventional automatic disturbance rejection controllers (TADRC). The simulation results show that under the interference of external uncertainties, the controller designed and the proposed control strategy make the DC link voltage overshoot smaller, the stability time shorter, and effectively improve the dynamic response performance and anti-interference ability of the system.