In the era of the digital economy, data, as a new production factor, is not only at the core of corporate competition but also one of the important driving forces for national innovation and development. Government departments at all levels accumulate a large volume of data across various fields in the process of performing their functions and social governance. These public data possess characteristics of considerable scale, rich diversity, and exceptionally high quality. They not only stimulate technological innovation but also belong to the realm of public resources, holding the potential to activate markets and guide innovative development. However, empirical analyses on the impact of government data openness on technological innovation are relatively scarce. This study utilizes panel data from 268 cities from 2009 to 2021, treating the gradual launch of government data openness platforms since 2012 as a quasi-natural experiment. Using a progressive difference-in-differences model, it examines the impact of government data openness on technological innovation and its mechanisms. The research finds that government data openness can promote technological innovation; this conclusion remains valid after conducting robustness checks such as parallel trend tests, placebo tests, and PSM-DID. Mechanism tests indicate that government data openness promotes technological innovation through three pathways: fostering the development of the digital economy, improving the business environment, and increasing entrepreneurial activity. Furthermore, heterogeneity analysis reveals that government data openness has a more significant promoting effect on technological innovation in higher-tier cities, eastern regions, and cities with high levels of big data. Government data openness also exhibits a spatial proximity effect, contributing to the enhancement of technological innovation levels in local and neighboring areas. Compared with previous literature, this paper makes several marginal contributions: firstly, while early literature primarily focused on exploring the theoretical connotations of government data openness, analyzing domestic and international case studies, and investigating related open institutional systems, this study addresses the lack of attention in existing literature towards the impact and mechanism of government data openness on technological innovation, both theoretically and empirically, providing a new viewpoint on the enabling role of government data openness and expanding related literature. Secondly, this study reveals and verifies the potential mechanism through which government data openness enhances technological innovation levels, providing strong evidence for understanding how government data openness enhances regional innovation levels and offering new perspectives and ideas for subsequent research. Finally, based on the heterogeneity of urban geographic locations and levels, this study deepens the understanding of the different enabling effects of government data openness on technological innovation. Additionally, it explores whether government data openness exhibits a spatial proximity effect to better understand its impact on technological innovation. In summary, this study provides important theoretical support for the practice of government data openness, offering suggestions for improving the quality of data openness, creating an innovative resource aggregation, and perfecting the digital infrastructure to foster a more conducive environment for innovation and entrepreneurship, so as to better leverage government public data to promote technological innovation.