To explore the impact of the changes of agricultural cropping-breeding mode(ACBM) on the water quantity and quality of rivers, Four Lakes Main Channel(FLMC) in the Jianghan Plain was taken as the research object. Based on observation data from 2010 to 2023, the trend of annual water quantity and quality changes was analyzed. Remote sensing images and statistical yearbook data were used to identify the interannual area change characteristics of different land utilization types, and redundancy analysis (RDA) was applied to explore the response of the main channel’s nitrogen and phosphorus concentration and flux to the changes.The results indicate that: ①In the past 10 years, there has been a significant change in the water quantity and quality of the main channel, and the water quantity has shown an increasing trend. The nitrogen and phosphorus concentration in the water body first increases and then decreases before stabilizing; The seasonal changes in water quantity and quality within the year are significant, with water quantity and nitrogen and phosphorus concentration reaching peak in summer and autumn from May to September. ②The spatial differences in nitrogen and phosphorus concentrations in water are significant, with nitrogen and phosphorus concentrations increasing first and then decreasing from the beginning to the end of the main channel. ③The ACBM in the Four Lakes Basin has changed significantly, with the proportion of shrimp-rice cultivation increasing by 23.3%, and the nitrogen and phosphorus agricultural non-point source loads increasing by 2763t/a and 829t/a, respectively; Single rice, freshwater aquaculture, and dryland crops decreased by 15.5%, 4.8%, and 3.0% respectively, while the nitrogen and phosphorus non-point source loads decreased by 1045t/a, 14672t/a, and 2758t/a, and the phosphorus decreased by 313t/a, 1667t/a, and 69t/a, respectively. ④The characteristics of nitrogen and phosphorus concentration changes in FLMC are significantly positively correlated with nitrogen and phosphorus non-point source load, with an explanatory power of 60.7% (*p<0.01). freshwater aquaculture and shrimp-rice cultivation are the main sources of phosphorus non-point source load, with contribution rates of 78.1% and 8.4%, respectively. Freshwater aquaculture and dryland crops are the main sources of nitrogen non-point source load, with contribution rates of 75.0% and 18.5%, respectively. ⑤In addition, the nitrogen and phosphorus flux at typical cross-sections of FLMC is significantly correlated with changes in agricultural cultivation patterns, the increase in nitrogen and phosphorus flux from 2010 to 2016 is related to the growth of freshwater aquaculture and shrimp-rice cultivation areas, while the decrease in nitrogen and phosphorus flux from 2016 to 2023 is related to the growth of freshwater aquaculture areas.