To explore the impact of changes in agricultural cropping-breeding mode(ACBM) on river water quantity and quality, the 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 use types and the trends of nitrogen and phosphorus point source load over nearly 10 years. Redundancy analysis (RDA) and correlation heat map were applied to explore the response of the main channels nitrogen and phosphorus concentration to the changes. The results indicated that: ① From 2010 to 2023, the concentration of total nitrogen and total phosphorus in FLMC exhibited an inter-annual pattern of “increase-decrease-stabilization”. The annual performance was lower in winter and spring, and higher in summer and autumn. Spatially, the concentrations were lower at the inlet and outlet and higher in the central reach. The annual displacement of the total trunk canal is mainly concentrated between April and September, accounting for 65.7% of the annual total. ② Over the past decade, the ACBM in the Sihu Basin has changed significantly. The dry land cultivation area decreased by about 15%, and paddy field area increased by about 19%. The freshwater aquaculture area increased by about 2% from 2010 to 2016, and decreased by more than 4% from 2016 to 2022. ③The variation characteristics of the total water quantity in the FLMC were not only affected by rainfall, but also related to the variation of rainfall-runoff of different land use types in the basin, among which paddy field and dry land were the main contributors, accounting for 366% and -236% of the total water quantity variation, respectively. ④ Over the recent 10 years, the concentration of total nitrogen and total phosphorus in the FLMC were positively correlated with the pollution loads (79.7% interpretation), and the main factors that caused the changes of N and P pollution loads in the basin were freshwater breeding and livestock breeding. In addition, the contribution of paddy cultivation to N and P loads increased from 6% to 26% in nearly 10 years, and the proportion of N and P loads gradually became prominent. This trend suggests that the risk of water environment pollution in the future cannot be ignored.