Abstract: Pot experiments in 3 phosphorus levels were conducted with 5 masson pine (Pinus massoniana) provenances in various areas to study the differences of root morphology and dry matter allocation of these provenances under low-phosphorus stress. The results showed that the aggravation of phosphorus deficiency would lead to the decline of the dry matter accumulation and main root parameters, while the allocation of dry matter to roots and the relative value of root parameters would obviously increase. Under low phosphorus stress, there existed significant differences between provenances tested for the dry matter accumulation and root parameters such as number of lateral roots. It was found that the provenance from Wuping of Fujian with the highest productivity under low phosphorus was an excellent provenance with the least sensitivity to phosphorus supply,followed by that from Xinyi of Guangdong and Chun'an of Zhejiang.This result was similar to that from field trials and liquid culture experiment. Genetic correlation analysis demonstrated that the provenances with extensive lateral root systems and more fibrous roots had greater dry matter accumulation. Some root parameters such as root volume, number and total length of lateral roots, and number of fibrous roots could be regarded as the efficient indexes for screening excellent provenances with high phosphorus efficiency in low phosphorus stress.