Abstract: Based on the analysis of the characteristics of faults and sand bodies, paleo-nose structures, fault activity and effective migration pathway index, the constitution and effectiveness of the migration system in the Tertiary of the Wen'an Slope of the Jizhong Depression and its effect on oil migration were studied. The migration system of the study area was mainly comprised of framework sandstones and many normal or reverse faults. Several paleo-nose structures towards oil sourcing sags located in the west of the Wen'an Slope and their match with the migration pathway system was favorable for oil convergence and migration towards the slope. Vertical migration was limited during large-scale oil migration, but lateral migration could occur through sand juxtaposition of different formations laterally adjusted by many NE faults. Ladder-like lateral migration over long distance from deep to shallow was the dominant migration pattern.