Abstract: To clarify the genesis and accumulation model of deep gas in Yingshan area of Songliao Basin, the geochemical characteristics and accumulation model of deep gas in Yingcheng Formation and Shahezi Formation were systematically analyzed based on the components and carbon isotope characteristics of gas as well as the pyrolysis, total organic carbon content and kerogen carbon isotope characteristics of source rocks. In Yingcheng Formation, oil-type gas mainly occurs, the source rocks are dominated by dark mudstone in Member 4 of Yingcheng Formation, the carbon isotopes of hydrocarbon components are relatively light, and the gas was accumulated in the late depositional period of Quantou Formation and Qingshankou Formation; in Shahezi Formation, only coal-type gas occurs, the carbon isotopes of the hydrocarbon components are relatively heavy, showing a positive sequence distribution on the whole, and the main hydrocarbon accumulation period is the late depositional period of Quantou Formation. In the late deposition period of the Quantou Formation, being mixed with coal-type gas from Shahezi Formation led to the reversal of δ¹³C₁＞δ¹³C₂ in some gas samples from Yingcheng Formation. The gas accumulation mode in Yingcheng Formation is characterized with near-source reservoirs, matched faults, and gas accumulation at the high point of structure; mudstones with high hydrocarbon-generating intensity control the distribution range of gas reservoirs; "uplift in sag" is the low potential zone for gas migration and the favorable directional zone for gas charging; the organic matching of "fault+trap" is the key to the formation of gas reservoirs. The tight gas accumulation mode in Shahezi Formation is characterized with integrated source and reservoir, overpressure driving, lateral near-source migration and accumulation; the macro distribution of gas reservoirs is controlled by the intensity of hydrocarbon expulsion from source rocks and overpressure range, while the gas reservoir scale is determined by the high-quality reservoir of "integrated migration and accumulation". The findings have important guidance and reference significance for deep gas exploration in the peripheral fault depression zone of Songliao Basin.