In order to reveal the relationship between the radial growth of Pinus tabuliformis plantations and the drought in the Loess Plateau, we took 30 sample plots of Pinus tabuliformis in Wuqi, Zhidan, and Yanchuan counties as the research object, and obtained the ground meteorological observation data of daily precipitation from 1961 to 2012 from 72 weather stations in and around Loess Plateau. We took the number of consecutive days without effective precipitation as a drought index, analyzed the correlation between drought types and different diameter classes of Pinus tabuliformis plantation, and thus assessed the drought risk of Pinus tabuliformis plantations in the Loess Plateau. Results showed that: (1) The mild drought in the spring and mild drought in the previous summer could inhibit the radial growth of Pinus tabuliformis, and the latter had more influence on the radial growth of Pinus tabuliformis. (2) The greatest drought risk of Pinus tabuliformis plantations in Loess Plateau was near the northwest border of the study area, where the plantations were under the most severe drought stress and therefore was the most unstable. The transition area between the sand area and the loess area to its south had the second highest drought risk assessment index. Most of the other areas had a relatively low drought risk assessment index and relatively stable Pinus tabuliformis plantations.