Grassland soil samples were collected respectively in the areas without obvious rocky desertification,the moderate rocky desertification region and the intensive rocky desertification region of the western Karst district,Guizhou province.The contents of soil organic matter(SOM) and different forms nitrogen were analysed.The variety range of SOM and different forms nitrogen is the widest in the intensive rocky desertification region and it is the narrowest in the areas without obvious rocky desertification.Analysis of variance indicated that hydrolysable and anmio-acid N content was significant between the moderate rocky desertification region and the areas without obvious rocky desertification,SOM and the other form nitrogen content wasn't significant in different regions.Based on the problems which were encountered in the research process,it put forward some subjects which would be studied in the research of rocky desertification immediately.