Sample of this research was drawn from Shanghai government’s open data portal (datashanghai.gov). By mining and surveying the opening datasets since 2012 (Initial online time) to September 8, 2017(survey time), this paper divided government data into inventory data and incremental data, and analyzed the update status of those two kinds of data from three aspects of continuity, timeliness and activity. Specifically, this study took four measures of update accumulation, update timeliness, update increase rate and update conversion rate to reflect the above three aspects.