This chapter presents a systematic comparative analysis of the petroleum geological evolution characteristics in 34 lacustrine oil-bearing basins (including depressions and sags) across China. It focuses on key aspects of source rock research, such as the depositional environments of source rocks across various geological periods, the thermal evolution of organic matter, and the mechanisms of petroleum generation, primary migration, and secondary migration. The study consolidates conceptual approaches related to the petroleum generation theory for lacustrine source rocks in China and provides detailed discussions of the following theoretical frameworks: Basin formation, petroleum generation, and reservoir formation theory; Limited-space petroleum generation theory of source rocks; Primary migration and reservoir formation in fluvial-deltaic sedimentary systems; Low-temperature catalytic cracking theory for petroleum generation in source rocks. These frameworks are integral to advancing the understanding of the petroleum geological characteristics and evolutionary processes in China’s lacustrine oil-bearing basins.