Abstract: The traditional export coefficient model for agricultural non\|point source pollution （ANSP） load estimation can not calculate the ANSP load in different stages. Based on the export coefficient model， the stage load estimation model of ANSP was established from stages of generation， discharge and export， respectively. In the stage model， the source of ANSP was divided into agriculture land， livestock and poultry breeding and rural living. Subsequently， Sichuan Province was taken as a case study area， and the total nitrogen （TN） and total phosphorous （TP） loads in each stage in 2012 was calculated by the stage model. According to the stage loads of TN and TP， the main pollution source and main polluted districts were analyzed in each ANSP formation stage. It was shown that agriculture land was the main pollution source in generation stage， while livestock and poultry breeding were the main sources of ANSP in both discharge and export stages. Moreover， main polluted areas with high pollution generation load intensity of ANSP were found， including Suining， Bazhong， Yaan and Deyang. Aba was the area where the biggest discharge load in per farmland area was found， and Suining was the region where the surface water was polluted the most seriously by ANSP in whole Sichuan Province. In conclusion， the stage load estimation model could calculate and assess the stage load of ANSP simply and effectively， and the present study could provide theoretical support for the control of ANSP.

Key words: agriculture non\, point pollution source, load, total nitrogen （TN）, total phosphorus （TP）, stage export coefficient model