The upper and middle interval of the third member of Shahejie Formation is important target strata for oil and gas exploration and development. Therefore, it is critical to have a thorough understanding of the sedimentary system of the target strata, which has long been considered as nearshore subaqueous fan or fan delta systems. However, through systematic core observation and logging facies analysis, it has been found that medium - fine sandstone and siltstone are the main composition of the strata, and well logging show typical coarsening-upward delta-front facies. Microfacies such as subaqueous distributary channel, interdistributary bay, mouth bar, sheet sand can be recognized. Based on correlation of connected Wells and the multi-attribute analysis of seismic, including RMS and amplitude, the plane distribution of sand bodies in 1 ~ 4 sand groups has been analyzed, under the guidance of delta front sedimentary model. According to sand body distribution, plane distribution map of sedimentary microfacies has been made. It is clear that subaqueous distributary channel and mouth bar distributed in leaf shape and extend from southeast to northwest are more favorable to oil reservoir. New understandings can provide geological basis for fine oil and gas exploration and development in Gubei area.