Abstract: Water resource is the core element for maintaining ecosystems and economic development. In recent years, China has actively carried out fundamental surveys of water resources to collect baseline hydrological data for regional water management. In this context, this study integrates GRACE/GRACE-FO, GLDAS and measured groundwater data to investigate the spatio-temporal changes of terrestrial water storage (TWSA), surface water storage (SWSA), and groundwater storage (GWSA) in Guangdong province from April 2002 to December 2024. Additionally, this study analysis driving factors of changes of regional water storage using precipitation, temperature, potential evapotranspiration, and water consumption data. The results demonstrate that: In Guangdong province, TWSA shows surpluses in its eastern and northern regions, with an overall rate of change of 0.19±0.09 cm·a⁻¹ and a consistency of 72.4% in relative change rates compared to the water resource bulletin data. GWSA saving function in the central and western regions limited by exploitation, and the correlation coefficient between GWSA and measured groundwater changes reached 0.73. The driver analysis revealed that terrestrial water storage changes correlated with meteorological factors in descending order of correlation strength: precipitation, potential evapotranspiration, and temperature, while exhibiting a negative correlation with water consumption. Regarding extreme drought and flood events monitoring, the drought index GRACE-DSI and standardized precipitation index (SPI) reach 51.9% and 62.5% agreement for identifying regional drought and flood events respectively, and effectively reflected the types of wet and dry years recorded in the water resource bulletin. The findings provide large-scale data references for fundamental surveys of water resources in Guangdong province.