Abstract: In regards of the thick oil reservoir of the Shuyi block in Liaohe oilfield, the interlayer is divided into five types as mud interbed, mud barrier, physical interbed Ⅰ, physical interbed Ⅱ, physical interbed Ⅲ, combining core and logging data. And the classification standards of those five types are defined. Based on the sedimentary environment of this region, the distribution characteristics and rules are analyzed. Under the condition of close-spaced well network, the distribution of the interlayers is random simulated and the lithofacies 3D model is established, which qualitatively reveals the space distribution in vertical profile and horizontal plane. This is significant in the remaining oil distribution research and the oilfield development planning.