Due to geological complexity and the heel toe effect, the production profiles of long horizontal wells are usually imbalanced, and as a result, premature water breakthrough is usually encountered. Once water breakthrough occurs, this phenomenon will reduce oil production. To maximize oil recovery, inflow-control devices (ICDs) are widely used.to create a uniform inflow profile. To date, known ICDs cannot meet all the ideal requirements throughout the well's life. In this study, based on the combination of a successive restriction mechanism and water swelling rubber, a novel autonomous inflow control device is proposed. Then, the rules of oil water two-phase flow through the novel design are studied by a numerical simulation based on optimized structural parameters, and the fluid property sensitivities are analyzed. Upon integration of the novel design into the test apparatus, flow tests are conducted. The influences of water content, inflow rate, and injection rate on the pressure drop are further analyzed to provide a guide to completion parameter optimization. The results demonstrate that the novel design has a simple structure. Its flow-resistance rating can be easily adjusted. Additionally, the design provides a significant oil and water resistance difference. The pressure-drop ratio of the water relative to oil can be up to 40. The deign has a large crosssectional flow area, providing high plugging resistance and high erosion resistance. Moreover, the design is not sensitive to flow rate or oil properties and has a wide application range. Reservoir heterogeneity should be given more attention than the heel toe effect when optimizing the completion parameters.