Abstract: 【Objective】 This study aimed to analyze the differences in drought tolerance of hybrid BC₁F₁ progeny materials between sugarcane and Erianthus fulvus， comprehensively evaluate the drought tolerance of these materials， provi-ding scientific basis for utilizing these materials in breeding drought-tolerant sugarcane.【Method】 Nineteen hybrid BC₁F₁ materials of sugarcane and Erianthus fulvus as well as their three parents were taken as research subjects. A pot experiment was conducted， in which conventional water supply （CK） and drought stress treatment were set to determine physiological and photosynthetic indexes. Analysis of variance， correlation analysis， and fuzzy membership function analysis were performed to evaluate drought tolerance of tested materials.【Result】 Compared with CK， the mean values of relative water content， net photosynthesis rate （P_n）， stomatal conductance （G_s）， and transpiration rate （T_r） of tested materials under drought tolerance decreased （drought tolerance coefficient<1.000）； the mean values of cell membrane permeability， malondialdehyde （MDA） content， superoxidase （SOD） activity， peroxidase （POD） activity， proline content， soluble sugar content， and intercellular CO₂ concentration （C_i） increased varied differently （drought tolerance coefficient >1.000）. The rank of mean membership values of each index for test materials showed that Yacheng 89-9 had the lowest mean membership value （0.235）， while Erianthus fulvus had the largest mean membership value （0.546）. Among the BC₁F₁ progeny materials， 16-5 exhibited the largest mean membership value （0.529）， while 16-6 had the lowest （0.279）. The correlation analysis results of indexes showed that an extremely significant positive correlation was found between cell membrane permeability and SOD activity （P<0.01， the same below） and an extremely significant negative correlation was found between cell membrane permeability and relative water content； a significant negative correlation was found between proline content and relative water content （P<0.05， the same below）； an extremely significant positive correlation was found between P_n and G_s as well as T_r； an extremely significant negative correlation was found between G_s and T_r； significant positive correlations were found between SOD activity and G_s as well as P_n； a significant positive correlation was found between chromosome number and relative water content， but a significant negative correlation was found between chromosome number of tested materials and MDA content as well as drought tolerance； a significant negative correlation was found between chromosome number of tested materials and drought tolerance. Based on mean membership values of physiological and photosynthetic indexes， 22 participating materials were divided into three types： highly drought-tolerant， moderately drought-tolerant and drought-intolerant. 16-5， 16-3， and 16-12 were highly drought-tolerant BC₁F₁ materials.【Conclusion】 Under drought stress， sugarcane has different regulatory abilities and focuses of response for different physiological indexes. Relative water content was an important index reflecting drought tolerance， and the change in physiological indexes influences photosynthesis. The chromosome number significantly influences drought tolerance of materials， but has no obvious influence on photosynthesis.