Abstract: Currently, the limited understanding for the ignition characteristics of ground deflagration devices in the flare system results in a very poor ignition performance. In this study, the dynamic process of flame propagation in the flash tube is analyzed by FLACS for a typical ground deflagration igniting device numerically. The effects of relevant parameters on the ignition performance are investigated, including the volume fraction and the filling proportion of combustible gas in the flash tube, as well as the length of flash tube. The results show that the average flame propagation speed in the flash tube can reach up to 155 m/s. The maximum peak overpressure in the flash tube is up to 2.5×10⁵ Pa, and thus the flash tube should have a sufficient pressure capacity. The inlet pipes of fuel gas and compressed air should be equipped with appropriate gas flow meters, respectively. The flash tube should be filled with a combustible gas with a volumn fraction of 9.5% to improve its ignition performance. Furthermore, the ignition performance decreases with the increase of the length of flash tube, especially when its length is longer than 35 m. The achievements can provide theoretical guidelines for the optimal design, the installation and the operation of the ground deflagration ignition devices.