As accelerating the opening-up and sharing of public data has become a core task of China's digital government development，it is of great significance to evaluate the micro-level value and mechanism of action of open government data. Based on data from Chinese A-share listed companies from 2009 to 2022，this paper employs the launch of prefectural-level government data platforms as a quasi-natural experiment to examine the impact of open government data on enterprise digital transformation. The study finds that open government data significantly promotes enterprise digital transformation，primarily empowering enterprises through three mechanisms:information transmission，risk response，and condition creation. The positive impact of open government data is more pronounced among enterprises in regions with low levels of digital economy development，those receiving fewer government subsidies，in the manufacturing sector，of smaller size，and with higher initial digitalization levels. Further research indicates that open government data has synergistic effects with policies such as "Broadband China"，"Information Benefiting the People"，and the national big data comprehensive pilot zones. It has a more significant effect on enhancing "underlying technology embedding" than on promoting high-level transformation activities such as "digital technology application"，and can improve enterprises' total factor productivity by facilitating digital transformation. This paper deepens the understanding of how data element policies，represented by open government data，influence China's digital economy development，and provides robust policy guidance for governments and enterprises to leverage open government data，unlock the value of data elements，seize new opportunities in digital economic development，and expand new frontiers for economic growth.