Groundwater, a vital hydrological cycle component, is essential in sustaining ecosystem functions and human livelihoods. The dataset presented herein, derived from the China Geological Environment Monitoring Groundwater Level Yearbook (2005-2022) compiled by the China Geological Environment Monitoring Institute, integrates long-term observational data from groundwater monitoring wells across China. The dataset comprises 11,911 monitoring points and 4,275,506 observation records, with each site providing five observations per month. To enhance its spatial and temporal coverage, the dataset was processed using the inverse distance weighting interpolation method, generating groundwater level raster data with spatial and temporal resolutions of 1 km and one month, respectively. Validation of the interpolated data demonstrated high accuracy, with regression coefficients and R2 values approaching 1 across multiple validation regions, and root-mean-square error and mean-square error metrics remaining acceptable. Spanning 2005-2022, the dataset is available in standard GeoTIFF format, rendering it ideal for geographic information system analysis. It provides a robust foundation for investigating groundwater dynamics, exploring interactions with surface ecosystems, and supporting sustainable water management practices.