Bottom water reservoir is the main reservoir type in the Caofeidian oilfield characterized by fluvial facies in Bohai Bay. It is developed by large-scale horizontal wells. Discontinuous interlayer distribution in the reservoir is the key factor that affects development of the bottom water reservoir. So it is very important to study the interlayer distribution and its controlling effect on the bottom water. Taking Massive sand in Caofeidian11-6 oilfield as an example，3D framework of the interlayer distribution was obtained through fine correlation of layers in the appraisal wells and pilot wells that penetrating into oil-bearing reservoirs. The interlayer distribution pattern in thick braided river reservoir was established according to the relationship between interlayer and production performance response of water cut rise，fluid production capability，formation pressure etc. And the control of the pattern on the bottom water movement was analyzed. The research suggests that two main phases of interlayers developed in the Massive sand longitudinally block some of the horizontal wells simultaneously. According to the bottom water blocking ability，the interlayers are divided into three classes：strong barrier，middle barrier and no barrier. This method guides the study of remaining oil distribution and adjustment strategy of the bottom water reservoir in middle-high water cut periods. Finally，23 adjustment wells have been deployed and the average incremental oil for single well is 17×104 t.