Abstract: With big data gradually becoming a key means of production in socio-economic life and governance, the comprehensive governance of data elements has evolved into an indispensable element of modern government functions. The establishment of a data governance body has been one of the important reform initiatives for China’s digital government in recent years, providing an organizational foundation for government management and data application. Mixed cross-sectional time-series data from 296 prefecture-level cities across China were collected for the period 2015–2021, and event history analysis (EHA) methodology was utilized to explore the patterns of the establishment of local data governance bodies, the characteristics of their proliferation, and the factors influencing them. It is found that (1) from the time dimension, the reform of data governance bodies conforms to the S-shaped cumulative distribution curve law; (2) the relationship between the educational backgrounds of the leading cadres and the different types of data governance bodies is not to be ignored; and (3) compared to vertical hierarchical pressures, horizontal pressures have a more significant effect on data governance bodies’ institutional reform has a more significant contributing effect.