Focussing on saline lacustrine palustrine sediments in the Pliocene upper Youshashan Formation (N22) in the NanyishanDafengshan area, a large of number of cores, thin sections, seismic and test data were used to study the sedimentary characteristics and genetic mechanism with the objective of analyzing the controlling factors and establishing a sedimentary model.The results show that: ① in the sedimentary period of the Pliocene upper Youshashan Formation (N22), saline lacustrine palustrine sedimentary environment developed in the NanyishanDafengshan area. Saltwater and freshwater frequently merged to form a unique ecosystem, developing adaptive aquatic organisms and microorganisms. The sedimentary assemblage of saline palustrine sediment was finally formed by the combined impact of biological, chemical, and physical sedimentation processes. ② The identification marks of saline lacustrine palustrine facies were clearly expressed mainly including bog soil and a large number of nearsurface exposed marks, accompanied by a combination of lacustrine palustrine facies microbialite and microfossils. ③ Seven types of lithofacies were developed in palustrine environment, and the sedimentary characteristics and controlling factors of main lithofacies were further analyzed. ④ The palustrine environment was divided into beach area, vegetative area and inundated area. Different sedimentary environments formed different sedimentary sequences and developed individual lithofacies assemblages. The sedimentary sequence of saline lacustrine palustrine facies was mainly composed of prograding parasequence, retrograding parasequence, and aggradation parasequence.