Abstract: Based on the RS and GIS methods, the authors extracted the land use / land cover information from aero photograph in November 2000, and got the 2003 data from field survey. We also got the slope degree data from measuring the topography map and combined with the land use /land cover data to dynamically monitor and analyze the status of land use and its suitability. The results showed that: (1) The land use changed greatly in the research site during 2000-2003. The slope farm land decreased by 35.9%, the orchard land increased by 28.1%, and the afforested land increased by 103%. The quality of ecology in the research site was improved largely. (2) In the research site, which stands for the typical loess hilly gully region, more than 50% of land was eroded. Over gully ridge distributed the most land from 8-15?and 15-25?. While the most land under gully ridge belong to <3? and >35?. (3) In 2003, the different land use types focused the different slope degree scope. 70.73％ of terrain land is less than 15?, 63.61% of orchard land less than 25?, 78.18% of forest and shrub land great than 25?, 75.49% of grass land is in the eroded gully region, where is greater than 25?. From the angle of soil and water conservation and natural suitability of land, the differentiation of land use/land cover is reasonable generally. (4) The research site still has slope farmland of 46.53km2 in 2003, which occupy 64% of 2000. 32.75% is great than 25?, the critical angle of erosion. Due to lacking the protection, erosion on this part of land happened very easily and increasingly, which is the big hidden trouble of soil and water loss. In the future, the key measure of converting the slope farm land and improving the ecology environment efficiently, is to justify the reasonability according to the slope degree differentiation, strengthen the land use planning, and get support from science and technolpogy.