Abstract: Abstract: The response of Caragana microphylla root system to soil moisture can reflect the growth status of the Caragana microphylla plantation. Most studies focus on the relationship between Caragana microphylla fine root and soil moisture distribution in the vertical profile. This study aimed to investigate the relationship between Caragana microphylla fine root and spatial distribution of soil moisture in Huanghuadianzi watershed (42°17'-42°33'N, 119°36'-119°53'E) in Inner Mongolia. In August 2015, three sampling plots (150 m×150 m) were chosen in a s field with 10 a Caragana microphylla (density of 2 m × 4m). The field had the slope gradient about 4°. A wasteland without Caragana microphylla was as a control. The average height of plant was 2.60, 2.38 and 2.23 m for the 3 sampling plots. Fine root was collected from 0-200 cm soil depth for the determination of surface area density. Soil moisture was measured by a QS-SFY soil moisture measuring instrument. EPSON10000XL scanner and WinRHIZO root analyzing system were used for measurement of the fine root-related parameters. Meanwhile, the dried soil layer was investigated in the profile. The results showed that the fine root weight in the 1-m soil depth accounted for 81% for the sampling plot 1, 78% for the sampling plot 2 and 74% for the sampling plot 3 of the whole soil depth, respectively. The correlation between the soil moisture along the vertical and horizontal direction and the fine root surface area density was extremely significantly high with the correlation coefficient above 0.65 (P<0.01). The spatial distribution of the fine root surface area density was consistent with that of soil moisture: the maximum value was right below of the sampling position and the minimum value was 50-70 cm. A model between fine root surface area density and soil moisture was built with R2=0.74 (P<0.05). After considering the spatial distribution of soil moisture, the model accuracy was improved to R2=0.80 (P<0.05). The validation of the modified model showed the R2=0.84 (P<0.01). It indicated that the fine root surface area density model considering the spatial distribution of soil moisture was reliable in predicting the fine root surface area density. The maximum field capacity and stable field capacity of the study area were 17.56%-22.01% and 10.50%-13.77%, respectively. The soil moisture distribution of the 3 sampling plots was consistent. The soil moisture in the 3 plots in the 200 cm depth was 3.47%-6.01% with a mean of 4.53%. The wasteland had the soil moisture of 5.10%-8.77% with a mean of 7.73%. The soil moisture of the wasteland was 71% higher than that of the sampling plot. There was at least a 200-cm dried soil layer in the Caragana microphylla land and the soil drying was the most serious in the 70-cm depth below the soil surface. In the 70-cm soil depth, the soil moisture was even closer to the wilting soil moisture. The study provided an evidence that the land with a single Caragana microphylla could lower the soil moisture and hinder the plant growth.