<p>Owing to the complexity and volatility of the contemporary international environment, strengthening economic resilience has become essential for ensuring regional sustainable development. In this context, the critical role of optimizing the productive factor endowment structure has become increasingly prominent, serving as an important potential lever to strengthen economic resilience. Taking water resource as a critical productive factor, this study employs the quasi-natural experiment of the South-to-North Water Diversion project in China to investigate how alleviating water shortage affects urban economic resilience and the underlying influence channels. The results show that mitigating water scarcity significantly improves the ability of recipient cities to withstand economic shocks. Mechanism analysis reveals that the South-to-North Water Diversion project strengthens urban resilience primarily through promoting economic structural transformation and boosting regional financial development. These findings suggest that improving the allocation of key bottleneck factors and thereby optimizing the factor endowment structure is an effective strategy to expand regional development potential, reshape development trajectories, and improve the resilience level of economic systems.</p>