In order to explore the root morphological plasticity of Alsophila spinulosa community affected by Phyllostachys heterocycla expansion,samples of mild,moderate and severe disturbance of Phyllostachys heterocycla were set up in Chishui Alsophila National Nature Reserve. The root systems of Alsophila spinulosa and Phyllostachys heterocycla were collected by root-drilling method. Their biomass density,specific root length of fine roots,and the distance between adjacent lateral roots were given detailed comparisons. The results showed that (1) The root biomass density of Alsophila spinulosa was much lower than that of Phyllostachys heterocycla under different impacts,displaying a negative correlation between them. (2) With the approaching of Phyllostachys heterocycla,the root biomass of Alsophila spinulosa continued to decline. (3) Fine root specific root length of Phyllostachys heterocycla was higher than that of Alsophila spinulosa in all plots. (4) The distance between lateral root nodes of Phyllostachys heterocycla was the shortest and the number of lateral roots was the largest under severe disturbance. (5) The roots of Phyllostachys heterocycla were mostly distributed in surface soil. Thus,we concluded that the root system of Alsophila spinulosa tended to be distributed in the deep soil gradually. In the process of expanding to Alsophila spinulosa forest,Phyllostachys heterocycla can maintain its dominance by changing the morphological plasticity characteristics of root biomass density,fine root specific root length,and adjacent lateral root node spacing.