The effects of foliar application of different concentrations of exogenous selenium on morphology and physiological characteristics of wheat seedlings under PEG-6000 stress were studied to provide a theoretical basis for exploring the effects of exogenous selenium on drought resistance of wheat seedlings. In this study, four wheat varieties (lines) including Shunmai 1718, Jintai 102, Jingdong 17 and S1204 (lines) were used as materials, four selenium concentration levels were designed, including distilled water (CK), 20 mg/L (Se20), 40 mg/L (Se40), and 60 mg/L (Se60) of Na₂SeO₃. When the second leaf of wheat seedlings was expanded, the leaves were sprayed with selenium and cultured for 2 days. Then 20% PEG-6000 was used to simulate drought and wheat seedling were continued to be cultured for 7 days. The morphological and physiological indexes of wheat seedings were measured. The results showed that exogenous selenium significantly increased the plant height, root length, root number, fresh weight and dry weight of different varieties (lines) of wheat seedlings (P<0.05); Exogenous selenium reduced superoxide anion (O₂^.-) and malondialdehyde (MDA) in wheat seedlings. With the increase of exogenous selenium concentration, except for the MDA content of Jintai 102, the contents O₂^.- of and MDA of other treatmens were significantly lower than CK (P<0.05). Meanwhile, exogenous selenium increased the activities of SOD and POD in wheat seedlings. With the increase of exogenous selenium concentration, except SOD activity of Jingdong 17 and POD activity of S1204, the activities of SOD and POD of other treatments were significantly higher than CK (P<0.05). According to the membership function values, the suitable treatments for Shunmai1718, Jintai 102, Jingdong 17 and S1204 were Se40, Se60, Se20 and Se60, respectively. The order of sensitivity to selenium is Jingdong 17 > Shunmai 1718 > S1204 > Jintai 102. The sensitivities of the four wheat varieties (lines) to selenium are different. In conclusion, the suitable concentration of exogenous selenium foliar treatment effectively increases the activities of protective enzymes such as POD and SOD, decreases the accumulation of active oxygen, alleviates membrane lipid peroxidation damage, enhances drought resistance ability of wheat seedlings, and promotes the growth of wheat seedlings under drought stress. The foliar spraying of exogenous selenium is an effective way to relieve the drought stress of wheat seedlings.