The biomass,soil characteristics and root distribution of 17-year-old pure Platycladus orientalis stand and Hippophae rhamnoides × Platycladus orientalis mixed stand were studied in Yongshou County,Shaanxi Province on the Loess Plateau.Results showed that mean height,diameter of breast hight and stand biomass in the mixed stand were 25.80%,36.88% and 128.23 % higher than those in the pure stand,respectively. Total biomass of each part in the mixed stand was higher than that in the pure stand.Compared with the pure stand,soil bulk density in the mixed stand was reduced.On the contrary,soil porosity,water capacity and moisture capacity were increased to a certain extent.Platycladus orientalis root system(diameter≤1 mm and 1～3 mm) in the pure stand was mainly distributed in the upper 60 cm of soil,yet those in the mixed stand were distributed more deeply and evenly.Distribution of Platycladus orientalis root system(diameter≥3 mm) in the mixed stand was close to that in the pure stand.Horizontal distribution area of Platycladus orientalis root(diameter≤1 mm and 1～3 mm) in the mixed stand was broader than that in the pure stand,while for root diameter greater than 3 mm,the distribution in the mixed stand was narrower than that in the pure stand.