Abstract: The overlap and erosion zones in northwestern margin of Junggar basin are characterized by frequent overlaps and erosions, far away from the hydrocarbon sources, and complex oil?gas migration and accumulation. Combining with geologic study, test analysis and basin modeling recognition, this paper analyzes the key factors of hydrocarbon accumulation and their matching relationships, and reveals that the overlap and erosion zones in this area have such pool?forming characteristics as charging by three sources and stages, transporting by faults?blanket sands?leached layers, and oil?gas accumulating by blanket sands margin?beneath weathering crust; the petroleum transporting styles include fault?blanket sand, fault?leached layer, and leached layer?blanket sand; and such hydrocarbon accumulation patterns as remote sources for hydrocarbon charging, fault?blanket sand?leached layer for oil?gas transportation, and the effect of transporting efficiency on controlling hydrocarbon accumulation and enrichment