Abstract: 40 years have passed since the reestablishment of the Qingdao Institute of Marine Geology in 1979. In the past 40 years, following the basic objective to carry out public oil and gas surveys in China seas and global waters with the Yellow Sea and East China Sea as major targets so as to meet the increasing demand of energy resources of the nation and society, the institute has devoted a lot to the studies on hydrocarbon resource generation and distribution patterns in China seas, upon the international frontiers of marine science and technology. A great number of breakthroughs have been achieved, such as the discovery of new oil and gas horizons and districts. Under the guidance of national energy strategy and the task to make China a strong marine power, the Institute has persisted in regional evaluation of oil and gas resources in China seas, in particular in the Yellow Sea and East China Sea. The research can be roughly subdivided into three stages: the first stage focusing on comparison of offshore and neibouring basins; the second stage focusing on the study of regional evaluation strategies of China seas and the third stage focusing on new horizons and new districts in the Yellow Sea and East China Sea. A map series on distribution of sedimentary basins in China seas and a set of dynamic situation map of oil and gas exploration and development in China Sea were compared and published successively. During the period, following achievements are necessary to be mentioned: (1) Breakthroughs in early stage oil and gas evaluation technology and the deep seismic detection technology for offshore sedimentary basins; (2) Resource assessment in China seas. Data proves that China is rich in marine oil and gas. And the next cycle of survey and exploration should be placed in the new horizons, such as gas offshore, buried hills oil and gas resources in the hydrocarbon-rich sags, oil and gas in deepwaters, organic reefs in the South China Sea and unconventional gas; (3) Further understandings of basic geology, such as, basement properties, marine stratigraphic sequences, tectonic division, characteristics of Jurassic foreland basins, marine basin hydrocarbon geologic conditions and favorable zones in the South Yellow Sea basins; (4) Solution of some specific geological problems related to oil and gas accumulation. Such as, Mesozoic stratigraphic sequences, two-stage basin architecture, basin properties, Mesozoic stratigraphic distribution patterns and the discovery of " Great East China Sea”, Mesozoic hydrocarbon geologic conditions and favorable zones in the East China Sea; (5) Discovery of Paleozoic reservoirs. These achievements and discoveries have laid a solid foundation for the future oil and gas geological survey and exploration in China seas.