Abstract: Based on the occurrences and characteristics of the gypsum and other markers, the sedimentary facies of the Paleogene saline lacustrine deposits in Wendong subdepression was studied, and the source rocks of different facies were evaluated according to the organic geochemistry analysis. It shows that the association of gypsum minerals reflects the changes in sediment environment, lake water depth, lake water salinity and bottom oxygen content etc., and possesses close relationship with sedimentary facies and source rocks development. Accordingly we established the saline lacustrine facies and source rocks development model. The saline mudflat and dry mudflat facies is dominated by disseminated, cemented and nodular gypsum minerals, the source rocks belong to no or poor source rocks with low organic abundance. The playa facies is dominated by enterolithic and lenticular gypsum minerals, has relatively high organic abundance and can form good to excellent source rocks. The saline deep lake facies is dominated by laminated gypsum minerals and can develop excellent source rocks with high organic abundance. This is of great significance in Paleogene saline source rocks evaluation of China.