Using the carbon emissions trading pilot policy implemented since 2011 as a quasi-natural experiment, this paper constructs a multi-period DID model based on panel data of 280 prefecture-level cities from 2006–2019 to explore the impact of the carbon emissions trading pilot policy on industrial structure upgrading and conducts a heterogeneity test and mechanism test. This study finds that the carbon emissions trading pilot policy significantly promotes the upgrading of industrial structures, especially for larger cities and non-resource-based cities. Further exploration of the impact mechanism shows that the carbon emissions trading pilot policy promotes industrial structure upgrading mainly through green innovation. The findings of the study have significant implications for the construction of a high-quality, modernized economic system in China.

With the advent of the “ear of high-speed railways”, the space–time distance between cities has drastically decreased. The opening of high-speed railways has not only increased the factor-flow speed across regions, but has also reduced the cost of factor movement. However, there is some controversy about whether high-speed railways can be used to promote regional economic growth. The Wuhan–Guangzhou high-speed railway is the earliest section of the Beijing–Guangzhou high-speed railway, and it was the first high-speed railway in China with a real speed of 350 km per hour. The Wuhan–Guangzhou high-speed railway opening spawned a three-hour economic circle in the south of China, injected new vitality into the economic and social development along the line, and had an important impact on accelerating regional economic interoperability and integration. Taking this into account, this paper took the Wuhan–Guangzhou high-speed railway as the case study. Firstly, this paper used the theory of system dynamics to analyze the mechanism of the impact of high-speed railway opening on regional economic growth. Secondly, the accessibility model was used to analyze the impact of the high-speed railway opening on the accessibility of cities along the line, and a difference-in-differences model (DID) was used to explore the impact of the high-speed railway opening on regional economic growth. Finally, on the basis of the analysis of the previous mechanism, the mechanism of the impact of the high-speed railway on regional economic growth is discussed. The results of this study show the following: (1) Since the opening of the high-speed railway, the accessibility of cities along the line has grown by more than 60%. (2) The opening of the high-speed railway has promoted regional economic growth, mainly through the influence mechanism of “increasing the total cargo volume”. This study not only scientifically and quantitatively analyzed the impact of the opening of high-speed rail on regional economic growth, taking the Wuhan–Guangzhou high-speed railway as an example for empirical analysis, but also further summarized the high-speed railway construction achievements in China and provides reference experience for planning the opening of high-speed railways.

As a new model of urban development, it is important to scientifically analyze the impact of smart cities on the quality of foreign direct investment (FDI). This article constructs a difference in differences’ model to test the impact of foreign direct investment quality in smart city construction based on panel data of 226 prefecture‐level cities from 2006–2017. Study shows the following. (1) The construction of smart cities has significantly improved the quality of FDI utilized in pilot cities. (2) Heterogeneity analysis shows that smart city construction significantly contributes to the quality of FDI in the western city subsample and a subsample of cities with low natural resource dependence. After a series of robustness tests and placebo tests, the above conclusions still hold. The results of the study suggest that China should further promote the construction of smart cities to optimize the quality of foreign direct investment and promote high‐quality economic growth. The findings of the study also provide theoretical and practical references for the construction of smart cities in China and other countries around the world.

Science and technology innovation is the new driving force of urban development, and it is an important vehicle to promote financial development. Innovative city attaches importance to the driving role of science and technology innovation capacity on industry development in the construction process, which will drive the development of the city’s financial industry. This article takes China’s innovative city pilot policy as a quasinatural experiment and uses the panel data of 235 prefecture-level cities in China from 2005 to 2017 to construct a difference-in-differences model (DID) to investigate the net effect and mechanism of the policy implementation on the financial development level of pilot cities. The results show the following: (1) the construction of innovative cities has significantly improved the financial development level of pilot cities, and the conclusion is still valid through the robustness test; (2) the financial development level promotion effect of innovative city construction has regional heterogeneity, and the financial development level promotion effect of central cities is more significant; (3) the construction of innovative cities can improve the financial development level of pilot cities by improving the intermediary effect of scientific and technological talents gathering and industrial structure upgrading.