Abstract:In order to understand the spatial distribution of sediment and nutrient under the impact of human activities, taking Yalong River and its first tributary Anning River as the research object, selecting the parallel section of Yalong -Anning River as the research area, six across sections along the river were selected, and the sediment concentration, nitrogen and phosphorus concentration were monitored vertically and transversely. The variation of sediment and spatial distribution characteristics of nutrient in different basins along the way were analyzed. The results showed that:(1) The sediment concentration of the Anning River was greater than that of the Yalong River, and the sediment concentration of the middle and lower reaches of these two rivers was higher than that of the upper reaches, and increased along the river. In the vertical distribution of sediment sections, there was no obvious stratification in Yalong River, while the stratification phenomenon of Anning River was remarkable,and the sediment concentration followed the order of bottom>surface>middle layer. In the transverse distribution of sediment section, except the middle and lower reaches of Anning River, the Yalong River and the upper reaches of the Anning River showed the right edge distribution. Generally, sediment uniformity of the cross section of Yalong River was better than that of Anning River. (2) TN and TP of Yalong River were significantly less than those of Anning River basin, and there were significant differences in spatial distribution of TN and TP of the parallel section of Yalong-Anning River in both vertical and horizontal sections. (3) There was a positive linear correlation between the concentrations of TN and TP and sediment in the parallel section of Yalong River. The fitting degree of transverse section was better than that of vertical section, and the correlativity between TN concentration and sediment was higher than TP. While for Anning River, the fitting degree of vertical section was better than that of transverse section, and the correlativity between TP concentration and sediment was higher than that TN.