Fine roots are highly heterogeneous in term of morphological structure and physiological function, which influenced the estimating of fine root longevity. Therefore, investigating the difference of fine root longevity among different root orders is crucial for our knowledge about fine root turnover and carbon allocation in terrestrial ecosystems. In this study, we analyzed the impacts of different factors (soil depth, seasons of birth, and horizontal distance from the plant stems) on lifespan of first-order roots and higher-order roots in a five-year-old Caragana Korshinskii plantation using Minirhizotron from 2007 to 2009. The site located in the Northwest Shanxi, east of the loess plateau region of China. The Minirhizotron tubes were installed at two horizontal distances (0 cm, 50 cm) from plant stems within the 100 cm soil depth. Results showed that: (1) The median lifespan were lower for first order roots than for higher order roots in all soil depths. The first order roots increased with soil depth. Higher order roots did not significantly change with soil depths, except for the surface soil (0-20 cm). The cumulated survival rate was above 50% in both 40-60 cm and 80-100 cm soil depths at the end of observation. (2)For seasonal scale, the median lifespan of first and higher order roots showed: autumn > summer > spring. In all seasons, the lifespan of first order roots was significantly higher than that of higher order roots (P < 0.01). However, it showed discrepancy between first order roots and higher order roots with seasonal change. For first order roots, lifespan in spring was significantly different from summer and autumn. For higher order roots, the differences of lifespan were significant between spring and autumn (P < 0.01); (3) For horizontal distance from the plant stem, the median lifespan of first order roots and higher order roots were higher at 0 cm than at 50 cm from the plant stems. The lifespan of higher order roots were significantly longer than that of the first order roots at the horizontal distance 0 cm and 50 cm(P < 0.01). Whereas, the lifespan of them varied between 0 cm and 50 cm from the plant stems. At the two horizontal distance, the lifespan of first order roots were significantly different (P < 0.01), but that of higher order roots did not show significant differences.