This dataset provides an improved global surface soil moisture product for the surface soil layer, named adjusted ERA5-Land dataset and created by fusing ERA5-Land and SMAP L4 data using a mean-variance rescaling method optimized for long time-series alignment. The dataset is validated against extensive global in-situ measurements from 1,615 stations with a total of 1.9 million measured soil moisture content. The dataset offers daily temporal resolution at a spatial resolution of 0.1°, covering the period from January 1st, 2015 to December 31st, 2020, and is provided in GeoTIFF files named by date (YYYYMMDD). The dataset can be further used for research and support drought monitoring, weather prediction, and water resource management, contributing to global climate resilience and informed decision-making across diverse ecosystems.