Abstract: 【Objective】 In this study, the roots architecture of Chinese fir(Cunninghamia lanceolate(Lamb.))under low phosphorus stress was explored in order to provide the scientific basis for improving nutrient use efficiency through the genetic improvement of root plasticity.【Method】 Five Chinese fir clones, propagated by tissue culture, were used for pot culture and irrigated with half-strength Hoagland nutrient solution with different KH₂PO₄(P)supplying levels(low P stress(PO), 0 mmol/L; suitable P(PN), 1.0 mmol/L). The biomass of the root, stem and leaf, as well as the root morphological indices and nutrient(P, N, K, Ca and Mg)accumulation and utilization efficiency were measured for plants of each clone after 60 d of culture.【Result】 ①The biomass and root morphological indices had significant genotypic effects with the change in P application level. ②Compared to plants under suitable P conditions, the biomass of the root, stem, leaf and whole plant were reduced by 20.06%, 20.68%, 14.07% and 16.78%, respectively, while the ratio of root to shoot showed an increasing trend. The total root length, total root surface area, and total root volume was increased by 17.31%, 17.69% and 24.77%, respectively. The average root diameter was decreased by 8.22% under low P stress. ③When supplying with an insufficient P solution, plant P accumulation and P content in the roots were reduced by 17.91% and 16.35%, respectively, there was no significant influence on P contents in the stem and leaf. Meanwhile, with the decrease of P accumulation, the use efficiency of P increased. Under insufficient P treatment, the accumulation of potassium, calcium, nitrogen and magnesium was reduced by 27.58%, 18.56%, 14.95% and 12.85%, respectively. ④Principal component analysis showed that root length, fine root length, ratio of root to shoot, and root dry weight were important morphological indices to low P stress. The result of analysis of regression showed that fine roots had a positive effect on P uptake.【Conclusion】 Chinese fir clones adapted to low P stress through the changes in root architecture, including reducing biomass accumulations of the stem and leaf, as well as the root diameter, and increasing the proportion of fine roots, prompting an increase in the ratio of root to shoot, and increasing the construction efficiency of roots.