This dataset is based on 58,033 sample plot data from China's Seventh National Forest Inventory (2004-2008), Landsat time-series data from 1985 to 2020, and other multi-source data (forest height, climate, soil, terrain, etc.). It estimates forest age by selecting optimal machine learning algorithms (such as RF, GBDT, CatBoost) for different vegetation divisions, and corrects forest age by detecting forest disturbance events from 1985 to 2020 using the LandTrendr algorithm. Finally, a 30m resolution forest age map of China in 2020 is generated. Independent validation shows that the R² value is 0.51-0.63, with a national average forest age of 56.1 years (standard deviation 32.7 years). The data can be obtained through the specified link and supports forest carbon cycle research and resource management.