Groundwater dynamics in the Rizhao Coastal Plain, primarily Quaternary porous phreatic aquifers, exhibit complex spatiotemporal variability driven by natural and anthropogenic factors. Using 2018-2020 monitoring data from 20 wells, the dynamic variation of groundwater in the Rizhao Coastal Plain was studied by applying empirical orthogonal function (EOF) decomposition, spatial analysis, and correlation analysis. EOF decomposition revealed distinct seasonal patterns: groundwater level fluctuations demonstrated lower interquartile ranges in summer-autumn than in winter-spring (p<0.05). Spatial analysis identified four principal components explaining 83.2% of the total variance (PC1 = 36.7%, P C2 = 2 4.2%, P C3 = 13.4%, P C4 = 8 .9%). P recipitation a ccounted for 45.6% of l evel variations, with anthropogenic activities (e.g., groundwater extraction) contributing 54.4%. By 2020, intensive extraction displaced the piezometric centroid southwestward, forming a new depression cone. To maintain aquifer equilibrium and prevent seawater intrusion, integrated management strategies are imperative: 1) Optimizing socio-economic spatial planning to reduce extraction pressure; 2) Implementing dynamic water allocation systems; 3) Establishing cross-sectoral governance frameworks for coordinated aquifer protection. This study provides a scientific basis for sustainable groundwater utilization in coastal plains undergoing rapid development.