Abstract: Associated with the new discovery of marine oil and gas in deep and ultra-deep formations, close attention has widely been attached on the high-quality source rock conditions of marine carbonate rocks in Micangshan area in the northern margin of Sichuan Basin. However, there is a lack of clear understanding on the complex hydrocarbon accumulation, transformation and adjustment processes. The scanning electron microscopy, fluid inclusions, U-Pb geochronology and other means are used to study fluid activity and bitumen characteristics in the Sinian Dengying Formation in Micangshan area, so as to identify multi-stage hydrocarbon accumulation, transformation and adjustment processes. Five stages of fluid activities generally occurred in Dengying Formation reservoir in Micangshan area, i.e., fibrous-fine crystalline dolomite (486 Ma±5 Ma) → medium-coarse crystalline dolomite (413 Ma±5 Ma) → saddle dolomite (268 Ma±8 Ma) → quartz/fluorite/lead-zinc ore (205 Ma±10 Ma) → bitumen (123 Ma±4 Ma). The lumpy, rim-shaped autochthonous bitumen and brecciated, broken allochthonous bitumen were commonly developed in dissolution pores. The spatial comparison shows that from Micangshan paleo uplift, piedmont zone, to the foreland basin, the bitumen abundance decreases as a whole, the autochthonous bitumen relatively increases and the allochthonous bitumen relatively decreases. The further mineral filling sequence study shows that the low-maturity organic hydrocarbon inclusions were mainly developed in fine and medium-coarse crystalline dolomite in the Late Cambrian-Silurian, while the mineral-captured inclusions such as saddle dolomite in the Middle-Late Permian and quartz in the Late Triassic had a relatively high maturity. In summary, the bitumen and inclusion characteristics show that Micangshan paleo uplift and piedmont zone were the paleo oil and gas accumulation center (gas generation and storage center) in the Permian-Jurassic. The primary oil reservoirs were damaged by late tectonic deformation, and the hydrocarbon migration and accumulation center moved to the foreland basin.