1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. Key Laboratory of Oil Shale and Coexistent Energy Minerals of Jilin Province, Changchun 130061, China;
3. Tianjin Center of China Geology Survey, Tianjin 300170, China

Based on the observation and analysis of core and well log data, the Sifangtai Formation in the northern part of Songliiao Basin is divided into two third-order sequences and eight fourth-order sequences, with two sedimentary facies and eight sedimentary microfacies identified. The Sequence 1 (SQ1) is braided fluvial facies, developing river bed and flood plain sub-facies in the lowstand systems tract period. Meandering river bed and flood plain (overbank and river flood lake) sub-facies occur during the transgressive systems tract period. Meander-ing river bed and flood plain (overbank, river flood lake and crevasse fan) occur during the highstand systems tract period and the regressive systems tract period. According to the geochemical analysis of mudstone samples, i. e., the variation trend of Sr/Cu, Th/U, Rb/Sr and SiO₂/Al₂O₃, it is indicated that the climate was hot and dry during the SQ1 period, and was weakened during the SQ2 period. The variation trend of δCe, V/Cr, V/(V + Ni), Ni/Co and U/Th show that the palaeo-water body during the Sifangtai Formation period was in the redox transition-oxi-dation environment, and was more oxidized during the SQ1 period. It shows a good coupling relationship between the paleoclimate, the paleowater's oxidation-reduction and sedimentary facies. When the climate is hot and dry, the evaporation intensifies, the water body becomes shallower and the water body is enhanced in oxidation, resulting in the development of a large number of river bed deposits. When the drought decreases, the evaporation slows down, the water body becomes deeper, and the oxidation becomes weaker, so as to be dominated by flood plain sub-faci-es.