Abstract: The aim was to explore the effects of polyethylene glycol (PEG) pretreatment with different concentrations (5%, 15%, 25%) on the germination, seedling growth and drought resistance of spring wheat seeds at two altitudes.‘Xinchun 11’planted at two kinds of elevation (1523 m, 795 m) were taken as materials, the seeds were divided into large, medium and small seeds in accordance with the 1000 grain weight. The results were as the following: vigor index, leaf area and root length of seeds with different sizes at the two altitudes reduced significantly along with the PEG mass fraction, and the germination rate also decreased, but not significantly. The root length of the seeds under the treatment of 5% was higher than that of the control. At high altitude, the root length of different sized seeds under treatment of 5% and 15% significantly increased compared with that of the control, the roots under treatment of 5% and 15% were also longer than that of the control at low altitude, but there was no significant difference between 15% treatment and control. Root length significantly decreased in the treatment of 25% at low altitude. Vigor index and leaf area showed large grain>medium grain> small grain in different PEG treats at the two altitudes, and there were significant differences among different sized seeds. The root length was small grain >medium grain>large grain. The indexes at high altitude were significantly higher than those at low altitude under the same concentration and of the same sized seeds. The result suggested that different mass fraction of PEG stress inhibited seed germination of‘Xinchun 11’; low mass fraction stress promoted root growth. The large sized seeds had strong resistance to drought stress compared with other sized grain seeds. High altitude seeds had higher drought resistance.