As a result of confusion about the reservoir sedimentary microfacies and the distribution rule of sand body in early the development of Li151 oilfield，the core，thin section，logging data and well performance definitely indicate the conclusion of division of microfacies，the spatial distributing of sedimentary facies and the relationship between sedimentary facies and oil-gas enrichment，which provide guidance for subsequence development.The results show that the Yan8-Yan9 layers are developed in sedimentary system of delta plain with 1-3 from SW to NE distributary channel（s），which laterally swung，as well as the number and dimension of distributary channel（s）at different periods changed along with the fluctuation of base level.The Yan10 layer is developed in sedimentary system as braided river with developed channel bar and thick sand body.The distributary channels，sand bar in channels，channel bar of braided river are favorable for the oil-gas enrichment.These achievements are of valuable significance to direct the progressive develop? ment of the reservoir.