The changes and differences of root functional traits of different tree species in dry-barren site were analyzed, and the adaptive strategies of different tree species to dry-barren environment were studied. The experimental materials were mainly ornamental tree species(C.coggygria, Amygdalus davidiana and Quercus variabilis) in the shallow mountain area with same age and stand density. Fine roots of trees were obtained by digging, and morphological parameters of fine roots were measured. According to the field water holding capacity and gravel content of the sample plots, four dry and barren gradients (light, moderate, heavy and extreme) were set. The root functional traits of three ornamental tree species were analyzed and compared, and then the difference of root morphology of different tree species in dry-barren site and their adaptability to special habitats were studied. The results showed that drought and barrenness had an impact on the root functional traits of trees, but the degree of influence on different traits and different tree species was different, and the impact on Amygdalus davidiana was the largest; The root functional traits of the three tree species varied significantly under different dry-barren grades, and the change of the same traits varied with tree species. From mild drought to extreme drought, the root link length (RL) of the three tree species decreased gradually, but the change of C.coggygria was not significant; The root tissue density (RTD) of C.coggygria and Quercus Variabilis variabilis decreased with the increase of dry and barren, but the Amygdalus davidiana increased with the increase of dry and barren; The specific root length (SRL) of C.coggygria and Amygdalus davidiana decreased from mild to extreme, and the SRL of Quercus variabilis increased with the increase of drought and barrenness; The specific root area (SRA) of C.coggygria increased with the increase of dry and barren soil, while the SRA of Amygdalus davidiana and Quercus variabilis decreased with the increase of dry and barren. Trees had a certain ability to respond and adapt to changes in dry-barren environments, which could adapt to the changing environment through their own morphological changes. Different species had different ways to adapt to the dry-barren environment, corresponding ecological adaptation strategies were adopted by balancing carbon allocation and carbon consumption. There were obvious differences between different tree species. Of the three tree species in this study, the root functional traits of C.coggygria did not change significantly in dry-barren environment, and the ability to tolerate dry and barren was strong; Dry and barren stress had a significant impact on the root traits of Amygdalus davidiana. By actively adjusting the morphological changes of the root system to adapt the changing environment, Amygdalus davidiana had a strong ability to resist dryness and barren; The fine roots of Quercus variabilis were abundant, so it could absorb soil moisture and nutrients, and could grow quickly in dry-barren environment.