Abstract: In order to explore the effect of drought stress on the growth of Allium mongolicum Regel seed at germination stage, and to screen out the germplasm materials with strong drought tolerance, five Allium mongolicum Regel seeds were selected as the experimental materials in this study, and polyethylene glycol (PEG) was used to simulate the drought stress (setting up four concentration gradients of 5%, 10%, 15% and 20%). By taking the distilled water (CK) as the control group, the germination rate, germinating energy, sprouting index, embryo length and vigor index of Allium mongolicum Regel seeds under different simulated drought treatments were determined, and the drought tolerance of various seeds was determined by using the principal component and membership function analysis. The results showed that with the increase of PEG concentration, the germination rate, germinating energy, sprouting index and vigor index of No.1 and No.4 Allium mongolicum Regel seeds showed a downward trend. The five germination indexes of No.2, No.3 and No.5 Allium mongolicum Regel seeds showed a trend of increasing first and then decreasing. Among them, when the concentration of PEG was 5%, it had obvious promoting effect on various germination indexes of No.2, No.3 and No.5 Allium mongolicum Regel seeds. When the concentration of PEG was 10%, the sprouting index of No.2 and No.3 Allium mongolicum Regel seeds was inhibited. Except for the index of embryo length, the other four germination indexes of Allium mongolicum Regel No.5 seed decreased significantly. When the concentration of PEG reached 15% and 20%, the germination and growth of Allium mongolicum Regel seeds were significantly inhibited. The evaluation of drought tolerance showed that the drought tolerance of 5 Allium mongolicum Regel seed during germination period was ranked from strong to weak as follows: No.3＞No.2＞No.5＞No.4＞No.1. The comprehensive drought resistance ability (D) of Allium mongolicum Regel No.3 seed was the highest, reaching 0.80, indicating that it had the strongest drought tolerance. The results could provide scientific basis and technical support for germplasm innovation, variety breeding and cultivation of Allium mongolicum Regel.