Brassica juncea (L.) Czern.et Coss has rich germplasm resources due to its unique characteristics of barren and drought tolerance. In order to study the low-P (low phosphorus) tolerance of B. juncea, 234 germplasm resources were surveyed at two phosphorus levels of normal phosphorus (250 μmol/L KH2PO4) and low phosphorus (5 μmol/L KH2PO4). The low-P tolerance coefficients of 12 traits such as shoot dry weight, root dry weight, shoot phosphorus concentration, root phosphorus concentration, among others, were investigated. The low-P tolerance of materials at seedling stage was preliminarily evaluated and screened by principal component analysis, fuzzy membership function analysis and cluster analysis. The results indicated significant variation among B. juncea seedlings under both phosphorus levels.Compared to normal phosphorus treatment, low-P stress led to a decrease in dry weight and phosphorus content, while the root-shoot ratio and phosphorus use efficiency increased of B. juncea. The low-P tolerance coefficient of 12 traits could divide 234 B. juncea four types, including low phosphorus tolerant, slightly low phosphorus tolerant (53 germplasms), slightly low phosphorus sensitive (105 germplasms) and low phosphorus sensitive (67 germplasms).The low-P tolerant accessions exhibited higher low-P tolerance coefficients for shoot dry weight, root dry weight, root-to-shoot ratio, and phosphorus accumulation, whereas the low-P sensitive accessions showed a higher low-P tolerance coefficient for shoot phosphorus use efficiency. This study provides a reference for evaluating low-P tolerance in B. juncea and offers valuable resources for mining low-P tolerance genes and breeding low-P tolerant varieties.