<p>Groundwater is the main source of water in Shouguang City, and fewer studies have been conducted on the hydrochemistry of Shouguang water source. This paper mainly analyzed its hydrochemical characteristics and causes by collecting groundwater samples from 1991 to 2022 and using statistical analysis, correlation analysis of hydrochemical characteristics, ion ratio analysis, Back Propagation neural network (BPNN) prediction and other methods. The results show that the groundwater dynamics in Shouguang is deeply affected by climate and human activities, with significant seasonal changes and precipitation leading the recharge, but the water level drops abnormally in rainy season due to over-exploitation, which highlights the urgency of negative resource balance and management. Hydrochemical analyses reveal the resilience of geochemical processes after abrupt changes in 2009 and are critical for assessing long-term stability. Piper diagram and ion analysis indicate carbonate geology, influence of saline intrusion on water quality, and ion correlation and ratio analysis reveal sulfate, evaporite contribution and cation exchange mechanism. Sulphate anomalies are associated with agricultural sulphide fertilizer application, revealing the potential impact of agricultural non-point source pollution. The BP neural network model accurately predicts the trend of ion concentration, and emphasizes the importance of monitoring and management to ensure the sustainability of Shouguang groundwater. The results of this study enrich the study of groundwater in Shouguang Water source to ensure the long-term sustainability of water resources.</p>