Abstract: Based on universal soil loss equation, the method combined with GIS and RS technology, The dynamic evaluation and analysis of soil erodibility in the soil erosion control area in the middle and upper reaches of Chishui River in Sichuan province from 2009 to 2013 were carried out, established R, K, LS, C and P five indexes, and by using spatial analysis function in intensity classification, statistics and analysis on the time and space, and main erosion factor identification. The results showed that the area of slight erosion was the largest in 5 years, reaching 70%~82%, with an increasing trend, and its retention rate reached 84%~94%, and the main erosion factor was C factor; Moderate erosion area accounted for about 20%, fluctuated between 14% and 22%, and the retention rate varied from 49% to 77%. The main erosion factor was C factor. The ratio of other erosion intensity areas was small, and the ratio of transformation to lower intensity was low.

Key words: soil erosion, dynamic evaluation, factors identification, GIS, RS