The paper discussed how basin structure influences the hydrocarbon accumulation in Muglad Basin, by studying the basin framework, tectonic evolution, structure character, the main trap types, and forming mechanism of different antithetic fault blocks. Research shows that antithetic fault block trap is the main trap type in Muglad basin, and there are two types of antithetic fault blocks developed in blk 1st，2nd，4th. The one formed by the stress adjustment of paleo uplift and slope zone, which is favorable to hydrocarbon accumulation and preservation due to its stable tectonic background; and the one formed by the strike slip and shear activity of the growth fault belt of Kaikang Trough, where hydrocarbon is hard to be preserved, as a result of intensive and multiple episodic movements. Besides, the basin structure character and differential tectonic evolution on both sides of Kaikang Trough determined the differential hydrocarbon accumulation rules. The east flank of Kaikang Trough has favorable trap and preservation conditions, due to Shelungo, Bamboo and Unity uplifts developed there and their stable tectonic settings. Meanwhile, the west flank doesn't develop such kind of uplifts and is composed of west slope and west growth fault belt. The west slope doesn't develop antithetic fault blocks, and the west growth fault belt has more intensive tectonic movements, which made the hydrocarbon accumulation in west flank is less developed than the east flank. And under the control of multiple tectonic activities of the west growth fault belt, multiple oil layers developed in the west slope area.