To reveal the effects of artificial Mongolian pine forest on soil particle size parameters in southern Mu Us desert, soil samples (taken as two layers 0—20 cm and 20—40 cm) under different plant densities (925～2 700 plants/hm2) as well as the bare sand land (control check) were selected in Yulin rare desert plant protection base of Shaanxi Province. Soil particle size parameters such as average particle size, standard deviation, skewness, kurtosis and fractal dimension were identified and calculated by using laser diffraction technique. The results showed that in the study area, majority soil particle size was occupied by sand particles, followed by silt particles and then clay particles. Soil particle size parameters presented comparatively thick, poor sorting, positive skewness as well as middle or sharp kurtosis. Fractal dimension of soil was in range of 1.422～2.084. As affected by Mongolian pine plantation, the average particle size and fractal dimension values were continue to increase leading to constantly particle distribution optimization than that of bare sand land, especially in the top layer of soil profile, such effects were more obvious. Meanwhile, there were no obvious regularities in standard deviation and kurtosis along with the increase of stand density. And distribution of soil particles was not balance. The results indicated that stand density factor was not enough to cause the thickness distribution of soil particles toward the trend of balance.