Abstract: As an advanced stage of China's urbanization process, the construction of smart cities plays an important role in promoting high-quality economic development. Based on panel data from 221 prefecture-level cities in China from 2006 to 2019, this paper uses a combination of propensity score matching and progressive difference-in-differences method to analyze the impact of smart city construction on high-quality economic development. The study finds that:Smart city construction significantly promotes high-quality economic development; The construction of smart cities has a heterogeneous impact on high-quality economic development;Smart city construction has a significant positive spatial spillover effect on high-quality economic development. Therefore, governments at all levels should actively expand the scale of smart city construction and the scope of pilot projects, differentiate the layout based on geographical characteristics, and deepen the cooperation and resource sharing among governments, so as to accumulate valuable experience for nationwide smart city construction, thereby promoting high-quality economic development in China.