Abstract: Based on the experiences of petroleum exploration, the control factors of hydrocarbon accumulation, reservoir distribution features and reservoir - forming patterns in abrupt slope zone with similar structures in Erlian and Bo- hai Bay basins, this paper profoundly studies the formation of the 3 structural styles in the northern abrupt slope zone in Baiyinchagan sag; analyzes the 8 types of traps in the zone and the effects of the 11 exploratory wells; and predicts that there exist 5 favorable exploration targets in the zone.