Phosphorus is a limited natural resource， but the utilization rate of phosphorus fertilizer in the current season is low， and excessive application of phosphorus increases the risk of agricultural non-point source pollution. It is an important way to save phosphorus resources and protect the ecological environment to excavate the genetic characteristics of phosphorus efficiency and cultivate low phosphorus tolerance varieties in potato. The establishment of an evaluation system of low phosphorus tolerance of potato varieties （lines） based on photosynthetic phenotypic parameters can achieve rapid， non-destructive and efficient identification and selection of low phosphorus tolerance potato germplasm. A total of 20 potato varieties （lines） were cultured in normal phosphorus nutrient solution pool （1.70 mmol/L NaH₂PO₄） and low phosphorus nutrient solution pool （0.17 mmol/L NaH₂PO₄）， and the biomass， yield and photosynthetic phenotype of each cultivar were measured. The low P stress tolerance index of each index was calculated. Using the comprehensive membership function method， principal component analysis and regression analysis， the low phosphorus tolerance of each potato variety（lines） was divided， and the low phosphorus tolerance of each potato variety（lines） was comprehensively evaluated. Compared with normal P stress， the average value of yield， plant dry weight and root dry weight of potato varieties under low P stress decreased greatly， with the coefficient of variation of each index ranging from 3.24% to 132.99%. The photosynthetic parameters， such as non-photochemical quenching coefficient （qN）， open ratio of PSⅡ reaction center （qL）， and quantum yield of non-regulatory energy dissipation（?no）， were increased. The cumulative variance contribution rate of five principal components was 86.32%. The membership function method was used to calculate the comprehensive evaluation value of low phosphorus tolerance （D）， and the D value ranged from 0.3258 to 0.7702. Using multiple regression analysis method， the D value regression equation was established to predict potato low phosphorus tolerance. Five identification indexes of low phosphorus tolerance were determined by multiple regression analysis and systematic clustering was carried out. The 20 potato varieties （lines） were divided into three types： low phosphorus tolerance type， intermediate type， and low phosphorus sensitive type. Red rose， 6-1， Dianshu 1520， Lishu 6， 27-1 and Dianshu 1208 were selected as low P tolerant varieties， while 86-2 and 54-2 were poor in low P tolerance and were P sensitive varieties.