Anti-erodibility refers to soil s ability to resist the dispersion and suspension caused by runoff.The study on anti-erodibility in the Beichuanhe Basin of Datong County, a national experimental site for conversion from cropland into forest land and grassland, shows that all the 12 anti-erodibility indexes can be divided into 4 categories, i.e.inorganic clay, aggregate, inorganic colloid and water-stable aggregate, capable of reflecting 85.6% of the informat ion of the eigenvalues, by means of PCA.All the plant communities in the Beichuanhe Basin can be clustered into three kinds based on the fo categories with the Hierachical Cluster Method.The first kind with good anti-erodibility mainly includes native forests, and the second kind with medium anti-erodibility is composed of artificial forests on rehabilitated lands of the early days, whereas the third with poor anti-erodibility is made up of newly established artificial forests in rehabilitated lands.The anti-erodibility of artificial forests is getting stronger and stronger as the forest ages, approaching that of native forests.It is successful to reafforest steep croplands in a natural way, and such artificial forests can play a good role in soil and water conservat ion based on anti-erodibility and other related eco-functions.