Abstract: In order to explore the feasibility of fire flooding technology for heavy oil in later stage of steam injection, an electrically heated igniter and auxiliary tools have been developed and ignition of oil reservoir at high temperature is realized; the combustion regime, live wire front location and advancing direction were judged through monitoring of live wire front, monitoring of components of produced gas and pressure-resistant down-hole temperature and pressure detection means; a multi-phase string flow temperature and pressure distribution model was built for vertical wells, fire flood working system and production fashion were determined, and auxiliary gas-proof tools were developed and the fire flooding and lift technology was created. According to various production stages by fire flooding and corrosion features of gas injector and producer, down-hole working conditions were simulated and indoor corrosion tests were carried out for oxygen corrosion and acidic gas corrosion, the tubular corrosion features were understood and the corrosion-proof technology was defined for gas injector and producer. Field tests show that this technology can meet the production requirement by fire flooding, and also proved the feasibility of converting to fire flooding of heavy oil reservoir in later stage of steam injection, providing technical support for similar reservoirs converting to fire flooding technology.