To explore the factors affecting the arc extinction performance of the self-disengaging lightning protection device,a numerical simulation model of arc extinction process of the device based on magneto-hydrodynamic theory is established in this paper. The effect of the initial phase angle of the current and the peak airflow velocity of the device on the arc extinction performance of the device is investigated,and the validity of the model is verified by high-current arc-burning tests. The arc extinction time of the device is related to the initial phase of the current,and it decreases with the increase of the initial phase of the current in the interval of 0°~180° electrical phase. The peak airflow velocity of the device is critical to arc extinction. When the peak airflow velocity of the arc extinction is higher than 243 m/s,the arc can be extinguished in half a period and the re-ignition is suppressed. When the peak airflow velocity of the arc extinction is lower than 243 m/s,the 'arc blockage' appears at the outlet of the gas arc extinction cylinder of the device,leading to the arc re-ignition. The findings of this paper provide a theoretical basis for optimizing the arc extinction performance of air-blown lightning protection devices.