Abstract: The establishment of national new areas serves as a pivotal national strategy, significantly contributing to the economic resilience of border cities. This study examines the impact of creating national new areas in Kunming and Harbin in 2015, utilizing panel data from 53 large and medium-sized cities spanning from 2010 to 2021. Through quasi-natural experiments, alongside the application of the synthetic control method and a difference-in-differences model, the research assesses the policy's effectiveness in bolstering the economic resilience of border cities. The findings reveal that: firstly, the initiation of national new areas markedly strengthens the economic resilience of border cities. Secondly, the positive impact on economic resilience is more pronounced in Kunming than in Harbin, indicating a heterogeneous policy effect across different cities. Thirdly, the enhancement of economic resilience in border cities through the construction of national new areas is primarily achieved by promoting industrial structure upgrading, although the mechanism through which industrial structure rationalization contributes to this resilience remains unclear. In conclusion, the paper suggests that government policy support should be intensified. National new areas are encouraged to focus on their strategic positioning, fostering the transformation and upgrading of the industrial structure, and to develop emerging industries with local characteristics that are tailored to regional conditions.