Abiotic stress of water and salinity can significantly reduce crop yield, which is one of the challenges facing agricultural production. Under the condition of water and salt stresses, the high root hydraulic conductivity is more conducive to the absorption of water and nutrients by plants and to the stability of yield. Therefore, it is of great significance to improve the root hydraulic conductivity of crops under water and salt stresses. Melatonin can effectively enhance the tolerance of plants to environmental stress, but its regulation mechanism on the hydraulic conductivity of roots is still not clear. The effects of melatonin priming on root hydraulic conductivity of super high yield wheat (Yannong 1212) under PEG-6000 and NaCl (simulated water and salt stress) were investigated in this study. Water and salt stresses limited plant height, leaf area, root length and root diameter of wheat in varying degrees, and the root hydraulic conductivity decreased by 51%, 58% and 93% (under water, salt and water plus salt). After wheat seeds were priming by melatonin, the leaf area, root length and root diameter of wheat increased under normal condition; the plant height and leaf area increased under drought stress; the root length and diameter increased under salt stress; under water and salt stress, melatonin increased the plant height, leaf area and root length, and restored the root hydraulic conductivity by 37%, 27% and 63%, respectively. Through the regression analysis of above mentioned parameters, it could be concluded that the main factors affecting root hydraulic conductivity were root length, leaf area and root diameter. The results indicated that melatonin priming is conducive to the popularization and planting of ultra-high wheat in arid/semi-arid areas.