With the advantages of large transmission capacity, low losses, rapid and flexible power regulation, and the ability to achieve non-synchronous networking, High Voltage Direct Current transmission systems are playing an increasingly important role in long distance transmission and grid interconnection. However, under certain circumstances, such as disturbances in the DC transmission system and sudden load changes, the converter based on PI control in DC transmission system suffer from slow response speed and poor stability. In order to improve the stability of the system and the response speed of DC voltage, this paper proposes an adaptive linear active disturbance rejection control (A-LADRC) method. The method is based on the analysis of the relationship between key bandwidth parameters and output quantities in linear active disturbance rejection control and enables adaptive adjustment of the controller bandwidth parameters for fast regulation of the DC voltage and to improve the stability of the DC voltage in the event of disturbances. Finally, the proposed control method is validated by simulation, and the results show that the proposed control method can effectively improve the response speed and robustness of the DC voltage, which has good practical engineering value.