Lakes are vital ecosystems providing essential functions such as water conservation, climate regulation, and biodiversity maintenance. Jiangsu Province, located in the lower reaches of the Yangtze and Huaihe rivers, is a typical region of shallow lakes in China where eutrophication remains a prominent issue. Due to the distinct natural geographical backgrounds and socio-economic development levels between Northern and Southern Jiangsu, the trophic states and driving mechanisms of these lakes exhibit significant regional heterogeneity. Based on long-term monthly monitoring data from 2011 to 2023, this study systematically analyzed the spatiotemporal evolution of water quality indicators and the comprehensive Trophic Level Index (TLI) in seven typical lakes: Lake Luoma, Lake Hongze, Lake Baima, and Lake Gaoyou in Northern Jiangsu, and Lake Ge, Lake Changdang, and Lake Gucheng in Southern Jiangsu. The driving mechanisms were further quantified using Random Forest (RF) models and Pearson correlation analysis. The results showed that over the past decade, the water quality of typical lakes in Jiangsu exhibited a distinct regional divergence. In terms of trophic status, Lake Ge and Lake Changdang exhibited the highest degree of eutrophication, ranging from light to moderate eutrophic states. Lake Baima, Lake Hongze, and Lake Gaoyou were categorized as lightly eutrophic, while Lake Luoma and Lake Gucheng were positioned within the critical transition range from mesotrophic to lightly eutrophic states. Trend analysis revealed that lakes in Southern Jiangsu exhibited significant water quality improvements, particularly Lake Ge and Lake Changdang, which were historically moderately eutrophic. Specifically, TN and TP concentrations in Lake Ge decreased by 1.96 mg/L and 0.087 mg/L (a 48.3% reduction), respectively, with its TLI dropping by 9.4. Conversely, lakes in Northern Jiangsu experienced a deteriorating trend. Lake Luoma transitioned from mesotrophic to lightly eutrophic as its TLI rose by 7.4, while Lake Hongze and Lake Gaoyou TLI increased 6.6 and 5.4, respectively. TLI values ranged across the study area from 47.36 to 61.01, with Southern lakes generally maintaining higher absolute trophic levels but showing better remediation progress. In terms of seasonal variation, Northern lakes exhibited significant differences between flood and non-flood seasons, with TLI values significantly higher during the flood season, whereas Southern lakes remained relatively stable throughout the year. Driver analysis revealed that water quality in Northern lakes was highly sensitive to hydrometeorological fluctuations. Increased precipitation and the resulting surge in inflow volume acted as the primary drivers of exogenous nutrient loading, further exacerbated by internal release under high temperatures and wind disturbances. In contrast, the improvement in Southern lakes was mainly attributed to landuse optimization and strict pollution control. The reduction in farmland (acting as a "source") and the restoration of forests and wetlands (acting as "sinks") effectively intercepted runoff pollution. These findings highlight the complexity of lake management under climate change and non-point source pressures, providing a scientific basis for differentiated eutrophication control and regional water security strategies in Jiangsu Province.