Through the investigation at 170 sample plots of soil and water forest in limerock region of Taihang mountain and the analysis of 13 qualitative and quantitative factors in each sample plot

the soil and water conservation forests are ordinated by methods of principal component analysis (PCA). The results show as follows:(1)The four types are divided in hilly region under the altitude of 500 meters. They are in turn:arbor，shrub and herb mixed model of Plutycladus orientalis and Gleditsia microphylla with above 20shrub coverage，arbor，herb and shrub mixed model of Platycladus oriehtalis and Pennisetum flaccidum with under 1000 shrub coverage，shrub and herb mixed model of Vitex neguzulo var. heterophylla and Ziziphus ju juba with a little litter，and Pehnisetum flaccidum herb wasteland without litter. (2) The four types in low mountain region(500一800m)are:arbor，herb and shrub mixed model of Platycludus orientalis

Pinus tahulaeformis and Vitex negundo var. heterophylla with under 10 shrub covevage，shrub and herb mixed model of Vitex neguud var. heterophylla，cotircus coggygria var. cizzerea and Ziziphas ju juba with above 5000 shrub coverage，herb slopeland mod-e1 of Pennisetum flaccidu}n

Themeda triandra and Pennisetum flaccidu}n，with above lOcm soil depth，and arid waste land model with under lOcm soil depth. These divided types characteristics are manifest and difference among these types is significant by statistical test. The classification are recognized as justified with high accurecy according to Fisher test analysis. These results conform to practical state in the area. The arbor，herb and shrub mixed model is regarded as the best model of soil and water conservation forest.