One of the essential requirements for high-performance dual active bridge (DAB) converters is to obtain the constant output voltage rapidly and accurately under different disturbances. To improve the disturbance rejection ability of DAB converters, this paper adopts an output voltage control method based on linear active disturbance rejection control (LADRC). Firstly, based on the reduced-order modeling method, the small signal transfer function of the DAB converter is derived and compared with the transfer function obtained by the swept-frequency method in the frequency domain. Then, the linear extended state observer (LESO) and the linear state error feedback (LSEF) control law are designed to estimate and compensate for the value of state variables and total disturbance. Finally, the simulation results in PLECS demonstrate that the LADRC method can maintain the output voltage stability more effectively than the PI controller.