Abstract: In the context of the tidal river network area of the Pearl River Delta, drawing inspiration from the water quality management concept of total maximum daily load (TMDL) in the United States, a strategy for the environmental governance of the Nanshunliananwei Water System was proposed, with the primary objective of achieving water quality target. Taking ammonia nitrogen (NH₃-N) as a representative indicator for the characterization of black and odorous water bodies, a simulation approach based on terrestrial pollution loads and water quality correlation models was employed. Following the conceptual framework of " pollutant loads calculation-environmental capacity assessment-pollutant loads allocation-engineering measures prediction", a refined NH₃-N emission control scheme was developed scientifically. Through simulation calculation, the pollution load of NH₃-N into the river can be reduced by 41.61 t/a through the source control and pollution interception projects. The water quality compliance rate in the river channels stands at 92.66%, marking a substantial increase of 35.92% compared to the conditions before the implementation of the engineering project.