A unique monthly NO₃− dataset at 0.25° resolution over China during 2005–2015 was developed by assimilating multi-source variables. The newly developed product featured an excellent cross-validation R² value (0.78) and relatively lower RMSE (1.19 μg N m⁻³) and mean absolute error (MAE: 0.81 μg N m⁻³). The dataset also exhibited relatively robust performance at the spatial and temporal scales. The dataset over China could deepen knowledge of the status of N pollution in China.