Abstract To explore the ignition performance of the ramjet combustion chamber, this paper combined the specific structure and working principle of the ramjet to model the ramjet combustion chamber, and carried out numerical simulation research on the flow field characteristics and combustion process of the stable operation of the combustion chamber. The results show that for the blunt-body of the flame stabilizer, the overall flame stability zone is relatively large at low inlet velocity, but the strength of the return zone at low inlet velocity is smaller than that at high speed. The flame stability zone formed at high inlet velocity is more stable and has stronger resistance to external disturbance. When the ratio of oil and gas mixtures is in the flammability limit range, the selection of ignition position has an important influence on the success of ignition. When the high-temperature zone formed by the initial ignition core can be diffused into the reflux zone and maintain sufficient temperature, the ignition can be successful.