The change of root architecture is an effective means for plants to adapt to environment. In this study, the root of Reaumuria soongorica and Salsola passerina were harvested by destructive sampling in the Alxa Plateau. The root architecture characteristics and adaptive strategy to arid environment were analyzed by root morphological, topology and fractal indexes. The results showed that the roots of the two desert plants were dominated by horizontal distribution and occupied different ecological niches. Large specific root length (SRL) and specific root area (SRA) values of R. soongorica (SRL =21.3 cm/g, SRA =7.6 cm²/g) and S. passerine (SRL=22.4 cm/g, SRA=6.5 cm²/g) were beneficial to obtain water and nutrients. Both R. soongarica and S. passerine roots were herringbone-like (TI, q_a, q_b being 0.86, 0.52 and 0.49 for R. soongorica, while 0.93, 0.76, and 0.73 for S. passerine) and had obvious fractal characteristics (FD and logK being 1.488 and 1.855 for R. soongorica, while 1.422 and 1.774 for for R. soongorica), which indicated that they had simple root architecture and high ability to expand living space. Above root characteristics may be the important adaptive strategies to arid environment for R. soongorica and S. passerina in Alxa Plateau.