Abstract: Multilayer interference fits are widely used in high-load mechanical structures, where their reliability is crucial for system stability and longevity. However, traditional stress-strength models often treat material properties and loading conditions as deterministic, overlooking inherent uncertainties and thus limiting the accuracy of reliability assessments. To address this, this study proposes a reliability design method for multilayer interference fits based on a fuzzy stress-strength interference model. By integrating fuzzy theory into the classical stress-strength model, a fuzzy reliability calculation model is established to characterize their mechanical behavior and progressive failure mechanisms. Based on thick-walled cylinder theory, the mechanical model and contact pressure formulas for multilayer interference fits are derived. The fuzzy membership function is then incorporated into the classical framework to construct the corresponding fuzzy reliability model. Using a wind turbine shrink disk as a case study, the proposed method is compared with traditional reliability algorithms and Monte Carlo simulations. The results demonstrate that, with Monte Carlo simulation as the benchmark, the proposed fuzzy reliability method reduces the maximum calculation error by 29% compared to conventional reliability design, offering a more precise theoretical tool and practical guidance for the reliability design of complex mechanical structures.