Significant challenges are encountered in the interlayer penetration of artificial fractures in thin interbedded oil and gas reservoirs, and the displacement and scale of offshore fracturing operations are constrained by platform limitations. Based on a deep sand-shale thin interbedded reservoir, numerical fracturing models with different mechanical parameter and in-situ stress combinations were established. The propagation characteristics of hydraulic fractures crossing single and multiple interlayers were studied using the cohesive zone model (CZM).The results show that layers with low elastic modulus, high tensile strength, low Poisson’s ratio, and high horizontal stress exhibit dual attributes. They are not only mechanical barrier layers that inhibit vertical fracture propagation but also energy-accumulating layers that cause fracturing fluid to accumulate energy and build up pressure. Vertical interlayer penetration and propagation of fractures are significantly controlled by rock mechanical parameters and in-situ stress parameters. This process is inherently dominated by a dynamic "pressure buildup–release" mechanism. The ultimate fracture height depends on the degree of contrast and distribution characteristics of interbedded parameters, which determine the cyclical pressure buildup intensity and release rate during interlayer penetration.In-situ stress is the dominant factor affecting interlayer penetration. High horizontal stress difference combined with weak interlayer stress difference tends to lead to uncontrolled fracture height growth, while low horizontal stress difference and strong interlayer stress difference help stabilize fracture height .and maintain fracture width. For reservoirs with weak interlayer stress difference, high horizontal stress difference, and significant Poisson’s ratio contrast, low displacement and high-viscosity fracturing fluids are recommended. These fluids can control fluid loss and fracture height, and are also conducive to increasing the fracture width of target zones. For reservoirs with strong interlayer stress difference, multi-layer combined fracturing using horizontal wells is not suitable. This study reveals the "barrier–energy accumulation" conversion mechanism and pressure buildup-driven effect of vertical interlayer penetration and propagation of fractures in thin interbedded reservoirs. The findings provide important guiding significance for optimizing the development of offshore thin interbedded oil and gas reservoirs under constrained conditions.