In the information age, public data held by governments has become an increasingly critical data element. How government data openness affects public service provision is directly related to residents’ welfare and is therefore of great practical importance. Using the entropy-weighting method, this study constructs a composite index of the level of public service provision, and applies the staggered DID model for empirical analysis. The results show that public data openness significantly promotes public service provision. In terms of mechanisms, the paper tests three channels: optimization of the market industrial structure, resident feedback, and public service investment. The findings suggest that data openness reduces information costs for enterprises and residents on the demand side, enabling them to articulate more rational demands and suggestions, while on the supply side, it encourages more effective government investment. The synergy between demand and supply thus jointly elevates the level of public service provision. Well-designed and orderly government efforts to open data and foster the healthy circulation of data can therefore effectively enhance public service provision and improve overall resident well-being.