With the acceleration of the global urbanization process, smart city policies are playing an increasingly important role in urban planning and management. The purpose of this paper is to explore the impact of smart city policy on the innovation ability of city science and technology, and to analyze the policy by using the method of difference-difference. First of all, this paper reviews the development of smart city policy and its implementation in different regions of China. Secondly, this paper systematically studies the impact of smart city policies on urban science and technology innovation through the difference-difference method and empirical research. The study found that smart city policies can significantly promote technological innovation activities in cities, improve innovation capacity, and promote economic growth. Finally, the paper explores the potential impact of smart city policies on urban sustainable development, as well as some possible policy rec_x005fommendations. To sum up, smart city policies play a key role in shaping a city’s scientific and technological innovation capacity and are of great significance for future urban development. The findings of this study can help policymakers better understand the impact of smart city policies to develop more targeted and effective policy measures to promote the integration of urban science and technology innovation with sustainable development.