The structural-depositional framework of Dongpu sag has a zonation from east to west and north to south. Through comprehensive analysis on the ratio of extensional and downfaulted rate and volcanic distribution, it is suggested that depositional period in Sha3 member is favorable to large-scale development of the hydrocarbon source rocks due to the small extensional rate and fast downfaulted rate and inactive volcanic activity in the north of Dongpu sag; thus that the south of Dongpu sag is not good for the development of the hydrocarbon source rocks in comparison. The structural-depositional evolution in the research area has impact on spatial combination of reservoirs and cap rocks and oil-gas migration and accumulation model. Abnormal pressure develops in Dongpu sag and the pressure decreases gradually from the subsag belt to the central uplift belt and western slope belt. So the central uplift belt and western slope belt become the directional areas of centrifugal flow that can provide favorable hydrodynamic condition for oil-gas accumulation under the role of buoyancy. The northern research area is more favorable for oil-gas accumulation than the south for better source-reservoir-seal combination and migration-accumulation conditions.