It is important and significant to know the spatial distribution pattern of fine roots for understanding the utilization status of the available resources belowground. The objective of this study was to investigate the fine root dynamics of Caragana korshinskii Kom, a shrub species widely planted to control soil erosion and land desertification in the semiarid area of China, in a 5-year-old plantation in the Loess Plateau area of Northwest Shanxi, China. Using the minirhizotron technique. The minirhizotron tubes were installed at two horizontal distances (0 cm and 50 cm) from the plant stems in the top 100-cm of soil. Based on the data sampled in the growing season (from April to September) of 2009, we analyzed the spatial-temporal patterns of fine root length density (RLD, mm/cm²) and fine root surface area density (RAD, mm²/cm²) in the plantation, and explored the relationships of RLD and RAD with the environment factors such as air temperature, soil temperature, rainfall and soil water content. The results showed that (1) there were certain differences in both vertical distribution patterns and seasonal change trends of fine roots between the two horizontal sites, and the obvious difference was that the values of RLD in the upper 0-60cm soil layers at the 0cm horizontal site were greater than those at the 50 cm horizontal site, and that the values of RLD (RAD) measured in every month for the former were larger than those for the latter. Therefore the RLD and RAD for the former (4.04 mm/cm² and 4.67 mm²/cm²) were significantly larger than those for the latter (3.07 mm/cm² and 2.99 mm²/cm²). (2) As a whole (for the average of two horizontal sites), the maximum value of RLD (RAD) appeared in 40-50 cm soil layer while the minimum value in 60-70 cm soil layer in the 100 cm soil profile. The RLD (RAD) showed a common seasonal trend with the peak value in the middle period of growing season. The total averages of RLD and RAD of fine roots in the growing season were 3.55 mm/cm² and 3.83 mm²/cm², respectively. (3) For 0 cm horizontal site, 50 cm horizontal site or the average of two horizontal sites (i.e. the plantation), the seasonal change course of RLD was significantly and positively related with air temperature and soil temperature, respectively. The above results showed that the horizontal distribution of the fine roots of young Caragana korshinskii was characterized by appearing mainly around the taproots, and the seasonal change trend of RLD was highly consistent with the change of temperature factor. Although the correlation coefficients between the seasonal change courses of RLD (RAD) and water indices (rainfall and soil water content) were not significant, this did not imply that fine root growth was not affected by water factor. Further research is required on the mechanisms of fine root dynamics in the annual growing season because of the internal and external controls of fine root growth.