The lacustrine lamina represents a sedimentary response to the sedimentary process and environmental change.The inner texture and genesis of carbonate laminae of Paleogene lacustrine shale in Dongying Sag were studied by thin-section analysis of core samples，scanning electron microscopy（SEM），and micro-fluorescence analysis. The results show that the Paleogene lacustrine shale carbonate laminae in Dongying Sag can be divided into micritic carbonate laminae and spar carbonate laminae，which are characterized by diverse mineral compositions and fabrics.Carbonate lens and lamina have a genetic relationship of inheritance，and the formation of carbonate laminae is closely related to microbial activities. The development and sedimentation of those laminae are controlled by both environmental conditions and their growth. A variety of mineral components confirm that lamina development has undergone a complex biological-chemical-physical process，and the inner texture and combination form of the laminae reflect the multi-cycle erosion–deposition activities. The development of lacustrine shale follows a sedimentary sequence from lens to laminae and from a single lamina to laminae couples，which records abundant geological information，such as changes of lake water environment，ecological evolution，and fluctuation in sedimentary base levels.