Abstract: To study the fourth member of Quantou Formation (Q4) in Yumin area, Songliao Basin, the principle of high-resolution sequence stratigraphy is combined with well logging and lithologic data to identify the sequence boundary and divide the strata, then establish the sequence stratigraphic framework, and finally analyze the sedimentary facies and distribution. The result indicates that Q4 can be divided into three mid-term cycles and seven short-term cycles, with development of meandering river and shallow delta facies, from which four sedimentary subfacies of river flood, riverbed, delta plain and delta front, and various microfacies can be identified. Based on the analysis of sedimentary facies types, lithologic association, plane distribution and vertical variation of sedimentary facies, the sedimentary microfacies maps of subdivision layers are drawn, which can provide prediction for prospecting favorable sand body.