<p><i>Glehnia littoralis</i> is a valuable Chinese medicinal plant whose wild populations are declining severely due to overharvesting and habitat degradation, making it urgent to identify suitable areas for its conservation and cultivation. This study combined the MaxEnt model with ArcGIS to predict its potential suitable habitats under current and future climate scenarios. Using 59 occurrence records and 17 environmental variables, we developed a high-performance model (AUC = 0.997). The results identified precipitation of the warmest quarter, elevation, and temperature seasonality as the dominant factors limiting its distribution to coastal regions in eastern China, with high suitability concentrated in Shandong and Liaoning provinces. The total area of highly suitable habitat under current climate conditions is approximately 1.09 × 10⁵ km². Future projections indicate a potential northeastward migration and a general reduction in suitable habitats. Furthermore, metabolomic analysis of 22 coumarins across multiple populations revealed that individuals from the Shandong Peninsula, which is one of the high-suitability habitats, accumulated significantly higher levels of key bioactive coumarins, including coumarin and marmesin. Correlation analysis further demonstrated that the accumulation of specific coumarins was significantly associated with the same key environmental factors, namely elevation, bio4, and bio18. This suggests that environmental conditions not only govern the geographical distribution of <i>G. littoralis</i> but also influence its chemical composition and bioactive potential. This integrated approach provides critical insights for developing targeted conservation strategies and sustainable cultivation practices for <i>G. littoralis</i>.</p>