Plant traits can be morphological, eco-physiological and phenomenological, studies of plant traits which relate to the key plant functions have primarily concentrated on leaf structure and physiology, however, much less is known about the interspecific variations in root structure and physiology. The specific root length (SRL) is one of the plant traits that are related to plant functions such as resource uptake, biomass allocation and root structure and function. It can not only reflect the environmental change, but also provide information about the shaping of itself by climate, soil nutrients or other factors. The vertical distributions of fine roots in the soil profile (080cm) for Bothriochloa ischaemum, Hippophae rhamnoidess, Quercus liaotungensis, which are three typical plant species in Loess Plateau were studied. The fine roots distributed from 080cm soil depth were collected for each 10 cm interval in each experimental plot, and then the fine root traits, soil water content, soil water stable aggregates and soil granules were determined in this study. The results showed that the SRL of Bothriochloa ischaemum, Hippophae rhamnoidess, Quercus liaotungensis, was ranging from 1855 mm/mg, 1440 mm/mg, 633 mm/mg in the 080 cm soil profile, respectively. Comparatively, the mean SRL (080cm) of three species stood in the following order of Bothriochloa ischaemum> Hippophae rhamnoidess> Quercus liaotungensis. The mean SRL in the 010 cm soil layer for three species were ranked in the order of Hippophae rhamnoidess> Bothriochloa ischaemum> Quercus liaotungensis, and that in the 1080 cm soil layer ranked in the order of Bothriochloa ischaemum> Quercus liaotungensis> Hippophae rhamnoidess. It is indicated that three species have different strategies for biomass allocation in different soil profile. The correlation analysis showed that the SRL was negatively correlated with the root biomass and root length density (RLD) for Bothriochloa ischaemum, however, it was positively correlated with the root biomass and RLD for Hippophae rhamnoidess. For Quercus liaotungensis, the SRL was negatively correlated with the root biomass, but positively correlated with the RLD. It is suggested that the interactions between root traits were dependent on species. The SRL of three species were all decreased with the soil water content increased. And the relationships between the SRL and soil water stable aggregates and soil granules indicated that different soil physical factors have different effects on the SRL.