Miaoxinan Sag is on the edge of Bohaiwan Basin and it is formed by the strong transformation of strike-slip fault.In order to study the controlling effect of strike-slip fault on hydrocarbon accumulation，the characteristics of strike-slip tectonic belt and the sag tectonic evolution was studied by means of variance slice and fine structure interpretation. The results show that there are two strike-slip fault branches in the study area：the east and the west. The east branch has obvious segmentation characteristics. The west branch runs through north and south. The forming of large trap groups are controlled by the flexural section and overburden area of strike-slip fault. The strike-slip fault activities in different periods had different controlling effects on hydrocarbon accumulation conditions. In the Eocene，the high-quality source rocks were developed at the intersection of strike-slip faults and extension zones in the southern subsag，and the environment of the intense transformation of strike-slip faults，high temperature and saline sedimentary was favorable to the early generation and early expulsion of hydrocarbon in the source rocks due to strong fault activities. In the late Eocene，strike-slip faults were coupled with the negative geomorphic units to form effective sand transport pathways，controlling the distribution of the delta sedimentary system. In the Oligocene，the formation of caprock in thick clay layers was controlled by the right-handed strike-slip pull-out action. In the Pliocene，two types of oil-gas accumulation modes：far-source convergence type and near-source vertical connection type were formed by the configurations of the strike-slip adjustment faults formed by the neotectonic movements，source rocks and structural ridges.