Abstract:    Since the reform and opening up, China has experienced nearly 40 years of rapid economic growth, made remarkable achievements, and has become the second largest economy in the world. However, there are still many problems in the economic and social development in China, which restrict the improvement of the quality of economic growth. The construction of innovative cities is an important institutional design to effectively enhance the ability of independent innovation and accelerate the transformation of the mode of economic development. The significance of the construction of innovative cities lies not only in innovation itself, but also in the transformation of economic development mode and long-term high-quality economic development. In 2008, Shenzhen was established as the first innovative pilot city. By 2022, there are 103 innovative pilot cities in China. The construction of innovative cities in China is a gradual reform process of "urban pilot-central summary-urban promotion". The development process has stage characteristics and gradually shows a trend of transformation from specialization to generalization. Does the construction of innovative cities effectively improve the quality of economic growth based on certain achievements? The exploration of this issue is of great significance for the comprehensive evaluation of the effectiveness of innovative city construction, the optimization of the development path of innovative cities, and the construction of innovative countries.
    Numbers of scholars have discussed the construction of innovative cities. Based on the relevant literature, it is found that the construction of innovative cities has had a wide impact on economic and social development. However, few scholars have explored the heterogeneous impact of innovative city construction on the quality of economic growth and its constituent elements. Further analysis of the internal impact mechanism is also urgently needed to be supplemented. This research focused on the relationship between the construction of innovative cities and the quality of economic growth, providing Chinese empirical evidence for "innovation driven development". Specifically, this research used urban panel data to estimate the impact of innovative city pilot policy on the quality of economic growth through the difference-in-differences (DID) method, and further analyzes its internal mechanism and heterogeneity based on the decomposition of components.
    The empirical study found that the construction of innovative cities significantly improves the quality of economic growth, and the construction of innovative cities promotes the technological progress and technological efficiency, but inhibits the scale efficiency of cities. A series of robustness tests have verified the above conclusions. Intellectual property protection and institutional environment improvement can strengthen the role of the construction of innovative cities in improving the quality of economic growth, and this role is stronger in eastern regions and cities with lower administrative levels. The construction of innovative cities mainly promotes technological progress through investment structure improvement and innovation incentive effect, and plays a role in technological efficiency through resource allocation optimization and industrial structure upgrading. The industrial competition effect and the entry substitution effect among enterprises are the main channels for the construction of innovative cities to affect scale efficiency. 
    This study aims to identify the impact of the construction of innovative cities on the quality of economic growth, deepen the understanding of innovation driven theory, enrich relevant research on China′s public policy evaluation. This study also provides new empirical evidence for "innovation driven development" and how to achieve high-quality economic development in the context of China. From the perspective of decomposition of constituent elements, this study deeply analyzes the theoretical mechanism and action path of the impact of innovative city construction on the quality of economic growth. While affirming the policy effect, this study proposes improvement directions for the future development of innovative cities, which has important policy implications for China to accelerate its entry into the forefront of innovative countries.

Key words:  innovative city, quality of economic growth, total factor productivity (TFP), mechanism analysis