Abstract: Based on core analysis and a large quantity of logging and log data as well as analysis of sedimentary characteristics, it is believed that two main subfacies, namely delta plain and delta front, developed in the 4th member of Quantou Formation in Yingtai-Da^’an Area of Northern Songliao Basin. They can be further divided into six microfacies, such as distributary channels, interdistributory bays, subaqueous distributary channels, subaqueous interdistributary bays, mouth bars and sheet sand. According to the study, the sedimentary microfacies had a controlling effect on the physical properties of reservoir and determined the sedimentary subfacies and oil and gas distribution. The results show that the different sedimentary facies and zones were quite different in physical properties and oil and gas properties. The subaqueous distributary channels and mouth bars were good in terms of physical properties and acted as the main facies and zones for oil and gas accumulations. They are the favorable targets for future oil and gas exploration.