According to present hydrocarbon exploration situation and survey at home and abroad, it is showed that the heterogeneity of hydrocarbon distribution not only occurred among different basins, but also appeared just in the same basin. Oil and gas mainly originated from a few petroliferous sags within the same basin, which is called hydrocarbon-rich sag. As to continental basins, the existence and the characteristics of hydrocarbon-rich sag control the quantity and size of petroleum resource in the basin, meanwhile significantly control and influence the formation and relatively concentrated distribution of large-medium scale oil and gas fields(reservoirs). The theory that hydrocarbon-rich sag controls the formation and distribution of oil and gas extends and deepens the previous theory that sedimentary basin and hydrocarbon source rocks control petroleum resources, which combined the integrity of macroscopic evaluation and prediction in the "Basin Control Theory" and the source relevance of localized evaluation in the "Source Control Theory". The theory of hydrocarbon-rich sag emphasizes that the identification and selection of hydrocarbon-rich sag in basins are the important and core content of petroleum exploration, evaluation and prediction. For hydrocarbon-rich sag, whether purposes of the frontiers of science exploration, basic theory research, oil and gas exploration or resource evaluation, it is all required to know the major geological conditions, dynamic environment and main controlling factors. This paper summarizes current research advances of hydrocarbon-rich sag in aspects as follows: (1) high production of organic matter in water body, (2) preservation and burial of abundant depositing organic matter, (3) characteristics of high quality source rocks, and (4) geological processes and effects on the formation of hydrocarbon-rich sag and high quality source rocks, including relationships between deposition and filling, geothermal field and thermal evolution, salinization of lakes, global/regional climate change and sea-level fluctuations, geological event and tectonic change, regional tectonic setting, etc. The current studies of the formation and main controlling factors of the hydrocarbon-rich sag, have many weak?links and controversial problems, which are mainly as follows: (1) in the aspect of research content and their importance, there are too many studies highlighting the characteristics and development of high quality source rocks, too few studies emphasizing the formation and characteristics of the hydrocarbon-rich sag itself; (2) about the approaches and forms of researches, too many works on "proceeding from the one to the other", too few works on the mechanism "from surface to inner essence" or "from results to causes"; (3) as to research area and types, too many works focus on eastern China, especially based on hydrocarbon-rich sag in offshore faulted-type basins, too few works mentioned hydrocarbon-rich sags in continental depression-type basins; (4) the studies about microbial contribution to high quality source rocks should be enhanced; (5) inorganic processes need to be emphasized; (6) the research on deep geologic processes and effects is weak; (7) the research results are influenced distinctly by appearance features of studied object and limitation of local conditions. Hydrocarbon-rich sag typically represents the partial enrichment of hydrocarbon resources distribution. Compared to marine basin, the forming of continental hydrocarbon-rich sag and high quality source rocks inside are more likely to be influenced by local geological environment and controlled by peculiar deep geological process. However, some main controlling factors or conditions that are necessary and sufficient are still unknown. Researching these especial phenomena demand not only a breakthrough in traditional thinking and pattern but also innovation in exploration for virtual achievement.