This study examines the causal pathways and heterogeneous characteristics of open government data on green technological innovation, using a multi-period difference-in-differences model based on data from Chinese A-share listed companies on the Shanghai and Shenzhen stock exchanges from 2011 to 2023.The findings reveal that open government data significantly stimulates corporate green technological innovation. The mechanism analysis indicates that this effect operates through optimizing corporate investment levels, promoting digital transformation, and enhancing operational management efficiency. Further heterogeneity analysis reveals that the promotional effect of open government data is more pronounced for enterprises located in key environmental protection cities, those without government-enterprise ties, those with high-level internal controls, and high-tech enterprises.