Abstract: Public data access is an important measure to promote the marketization of digital elements, and it is of great significance to study the innovation effect of public data access to enhance urban innovation capacity and promote the high-quality economy. Existing literature has largely focused on the role of digital economy policies in shaping urban innovation capacity, yet few studies have examined the impact of public data access policy on urban innovation capacity from a quality enhancement perspective. Based on the panel data of prefecture-level cities and above, this paper evaluates the impact of the implementation of public data access policy on urban innovation capacity and its action path through a multi-period double difference model. The results show that the opening of public data has significantly improved the urban innovation capacity. The analysis of transmission mechanism shows that the opening of public data has significantly improved the urban innovation capacity through the way of "government governance" to increase government expenditure on science and education and the way of "market vitality" to enhance market openness and entrepreneurial activity. Heterogeneity analysis shows that in northern cities, cities with high economic development level, low financial investment and high level, the innovation driving role of public data openness is more significant, and the promotion role of public data access is enhanced with the improvement of urban innovation capacity. This paper enriches the research results of urban innovation from the perspective of public data resources, and provides important policy enlightenment for promoting the reform of public data access, deepening the innovation-driven development strategy and promoting the coordinated development of urban innovation.

Key words: public data openness, urban innovation capacity, government governance efficiency, market dynamics