Abstract: The Penglai 19-3 ultra large integrated oilfield is one of the typical representatives of oil and gas accumulation of the Bohai Oilfield in the Tan-Lu Fault zone. At present, tertiary petroleum geological reserves of the oil field have reached 1 billion tons, but there is no targeted report on the formation mechanism of its large-scale traps. To clarify the formation mechanism of traps in Penglai 19-3 Oilfield, geological data were analyzed based on 3D seismic, drilling, structural forward simulation, sandbox physics simulation, and so on. It was believed that the contractional strike slip transfer zone controlled the formation of large traps in Penglai 19-3 Oilfield, and the controlling effect was further explored. The Penglai 19-3 structure is a large-scale antiform structure controlled by multiple levels and types of transfer zones, characterized by "intermittent contractional uplifting" and "structural finalization during hydrocarbon expulsion". The large traps formed have a good spatiotemporal configuration relationship with late hydrocarbon expulsion from cap rocks and source rocks. The study of the transition zone has certain reference significance for finding large and medium-sized oil and gas fields in the strike-slip fault zone in the future.