Offshore thin interbed sandstone reservoirs are an important part of future production succession. The characteristics of thin interbed sandstone reservoirs are different from conventional multi-layer sandstone reservoirs, and the interlayer interference in the production process is extremely serious, which leads to great differences in the development effects of each layers. Aiming at the characteristics of thin interbed sandstone reservoirs, this paper introduces the concepts of interference coefficient and flow capacity coefficient, and integrates many key factors of each layers such as injection-production connectivity, physical properties, fluid properties, and water flooded degree to establish quantitative evaluation method of interlayer interference law in thin interbed sandstone reservoir. By further revising the traditional directional well productivity formula, the directional well productivity prediction methods for thin interbed sandstone reservoirs have been established. This research methods have been applied in actual oilfields and achieved good effects. The results show that: ①The interlayer interference law of thin interbedded sandstone reservoirs is different from that of conventional multi-layer sandstones. The injection-production connectivity of each layers, reservoir physical properties, fluids, and water-flooding all have great impacts on the development effect; ②Flow capacity grade 5.0 can be used as the standard for layer division in thin interbed sandstone reservoir, and a reasonable time should be selected for stratigraphic adjustment and reorganization in the later period; ③The research method considering comprehensive factors has high prediction accuracy, and strong on-site practicability, which provides a strong support for this kind of oilfields.