Abstract: The emission coefficient method was adopted to estimate the pollutant emissions in planting, livestock breeding, aquaculture industry and rural life of three small watersheds in Changlinhe Town. The pollution evaluation was carried out by equivalent pollution load method, combined with water quality monitoring results in-depth analysis of agricultural non-point source pollution. The results showed that the chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) emissions in Changlinhe Town were 294.99, 56.41 and 6.41 t in 2021, respectively, and the COD emissions were the highest. The equivalent pollution load of the planting was the highest, accounting for 44.18% of the total emission standard, followed by rural life sources, accounting for 37.59%. The equivalent pollution load of TN accounted for 54.65% of the total emission standard, higher than that of TP and COD. Luodian, Luohong, Dongguang and Changlin community had a large equivalent pollution load, and the sum of the equal standard pollution load ratio of these four communities was 62.75%. Agricultural non-point source pollution was dominated by planting industry, in the future, pollution prevention and control should focus on planting industry and the main pollutant of TN should be controlled particularly, and the key control area is the Changlin River Basin.

Key words: agricultural non-point source pollution, emission coefficient method, sources analysis, evaluation, equivalent pollution load method