Abstract: In order to screen and identify drought-tolerant yield and drought-tolerant traits of 12 brassica juncea varieties, the grey correlation degree and principal component analysis were used to analyze the changes of 17 traits under drought treatment and normal irrigation. The results of grey correlation analysis showed that the most closely related factors were yield related factors, and the least closely related factors were stomatal conductance. Under normal irrigation, yield per plant was closely correlated with intercellular CO₂ concentration（0.636）. The drought-tolerance coefficients of 17 characters under drought stress were integrated into 5 independent comprehensive indexes by principal component analysis. Therefore, the yield factors, plant morphology factors and photosynthetic growth factors closely related to single plant yield should be observed in the selection of drought-tolerant varieties.