In-situ combustion refers to continuously injecting air into the formation and igniting it. Relying on the cracking and viscosity reduction of crude oil, as well as the multiple displacement effects such as the heat generated by combustion, flue gas, and steam, the crude oil is displaced to the production wells. It has technical advantages such as high oil recovery rate and low energy consumption. During the in-situ combustion process, a large amount of flue gas is produced (gas production-injection ratio is about 85%), and its main components are N2(about 82%), CO2(about 15%), etc. With the extensive application of in-situ combustion technology, the treatment and resource-based utilization of flue gas have become key links in the in-situ combustion technology series. How to treat the in-situ combustion flue gas with low cost and high efficiency has become an important factor restricting the expansion of in-situ combustion technology. Therefore, it is urgent to explore the technology of injecting flue gas back into the oil reservoir to enhancing oil recovery. Based on the flue gas reinjection test of the fault block A in Xinjiang Oilfield, this paper conducts the research on the injection-production technology of enhancing oil recovery by reinjecting the in-situ combustion flue gas into light oil reservoirs, aiming to provide a brief reference for the future field practice.