Variation laws of growth conditions and root cortical aerenchyma (RCA) of 15 common maize hybrids (Zea mays L.) in Yunnan Province under simulated rare extreme drought and rehydration conditions were tested in this paper. The relationship between functions of root tissues in extreme drought process and resilience after rehydration was discussed. Results demonstrated: 1) in middle drought period, RCA area is closely related with drought resistance of varieties and 2) Varieties with large or small RCA area under drought stress have poor resilience after rehydration, while varieties with middle RCA area present strong resilience. We concluded that RCA area formed under drought stress will significantly influence recovery of root functions during rehydration. Large RCA area brings corn strong drought resistance, but it goes against recovery of root functions after rehydration. Small RCA area causes poor drought resistance of corn plants, which will induce serious damage to plants and make it difficult to recover root functions after rehydration. Moderate RCA area helps corn variety to develop certain drought resistance and recover functions of root tissues through further formation of RCA area by parenchymal cells in root cortical tissues. RCA area formed in corn roots can affect drought resistance significantly, and increased RCA area in root system after rehydration can enhance resilience of corn plants.