Soil erosion on the Loess Plateau is serious due to precipitation,temperature,and other natural climate constraints and thus,determination of an appropriate stand density becomes very important. In this study,we conduct a systematic research on several aspects of the existing plantation in Caijiachuan,such as stand growth status,water storage capacity of forest litter, biodiversity,and physical properties of soils. Results show that,in order to improve the growth conditions,biodiversity,and soil physical properties,the best planting density of black locust,Panus,and the mixed forest should be 1 325,1 733,and 2 089 plant/hm²,respectively,whereas by considering the water storage capacity of the forest litter,the result turns out to be 2 133,2 222,and 2356 plant/hm²,respectively.Besides,the mixed forest has the highest biodiversity index and evenness index and the nor-capillary porosity and the capacity of the water conservation of forest soil in locust forest are also the host.