Abstract: Taking three kinds of artificial forests（Prunus armeniaca forest, Caragana korshinskii forest, Hippophae rhamnoides forest） in Zhongzhuang small watershed of Pengyang in Ningxia as the sample sites, and the farmland was used as the control, soil samples in 0—100 cm soil layer were collected by field standard method, and soil particle size composition was determined by Mastersizer 3000 laser particle size analyzer.Fractal dimension of soil volume was calculated by fractal geometry method, and soil nutrient related parameters were determined.The fractal dimension of soil particles of different artificial woodlands and their relationship with soil structure and nutrients in the loess region of southern Ningxia were studied, in order to provide reference for the health evaluation and rational management of forest soil in the region.The results showed that, 1)the soil grains characteristics of different artificial woodlands were different, the clay, silt, sand and fractal dimension were significantly different among different woodlands（P＜0.05）.The general pattern of soil fractal dimension was Caragana korshinskii forest＞Prunus armeniaca forest＞farmland＞Hippophae rhamnoides forest, which was consistent with the change of clay size.2) The contents of soil organic matter, available nitrogen and available potassium decreased with the increase of soil depth, all had obvious surface polymerization, while the contents of total nitrogen, total phosphorus and total potassium fluctuated with the change of soil depth and had no obvious change rule.The soil nutrient contents of different woodlands were significantly different（P＜0.05）,and the overall pattern was farmland＞Caragana korshinskii forest＞Prunus armeniaca forest＞Hippophae rhamnoides forest.The contents of soil organic matter, available nitrogen and available potassium decreased with the increase of soil depth, and all showed obvious surface cohesion.The contents of total nitrogen, total phosphorus and total potassium fluctuated with the change of soil depth and had no obvious change rule.3) The fractal dimension of soil was significantly positively correlated with the contents of clay, silt, total phosphorus and total potassium（P＜0.05）,and was significantly negatively correlated with sand（P＜0.01）.