<p>In this paper, we address the critical safety issue of traditional multiscale structures losing functionality under local damage and propose a novel multiscale fail-safe topology optimization method to enhance the robustness of multiscale structures. The method adopts a simplified local damage model and aims to optimize structural safety by minimizing strain energy under the most critical failure scenario. The macroscopic equivalent performance of the microstructure is evaluated using the homogenization method, and parallel topology optimization is employed to design structures at both macroscopic and microscopic scales. To resolve the non-differentiability of maximum strain energy, the Kreisselmeier-Steinhauser function is introduced as a substitute. Numerical simulation results demonstrate that this method effectively enhances the safety of multiscale structures by providing additional load-bearing paths to resist local damage. Compared to other fail-safe topology optimization methods, this approach expands the design space while maintaining the same computational cost and does not require adjustments to predefined microscopic structure configurations for different working conditions.</p>