【Objective】 In this study, the root morphology of different poplar (Populus sp.) clone seedlings under waterlogging and flooding treatment was explored, and the adaptive strategies of the poplar root system were elucidated to provide a scientific basis for the selection of poplar clones. 【Method】 Five poplar clones, i.e., 3804, 1388, 895, 110 and 328, were selected, and three treatments, i.e., control, waterlogging and flooding, were set up to determine the effects of different treatments on root characteristics such as biomass, total length, quantity, surface area and volume. 【Result】 ① There was no significant difference between the control and waterlogging groups in terms of poplar root biomass; however, in the flooding group, root biomass was significantly lower than that in the control group. ② No significant difference was found in terms of the number of first-order roots of most poplar clone stecklings between the treatment and control groups, but the total root length, projection area, surface area and volume were greater in the treatment groups than in the control group. ③ Compared with the control group, the treatment groups had decreased average root diameter but had increased number of root tips, root forks and root crossings. ④ The cumulative contribution rate of the two principal components extracted by principal component analysis was 88.58%, which may reflect the root morphological characteristics of poplar clone stecklings. 【Conclusion】 Subordinate function analysis showed that the order of the poplar clone stecklings based on root morphological performance for both treatment was as follows: waterlogging treatment, poplar 1388 > poplar 895>poplar 3804>poplar 110>poplar 328 and flooding treatment, poplar 1388>poplar 895>poplar 110>poplar 328>poplar 3804. In conclusion, based on the root morphology, we suggest that poplar 1388 and poplar 895 are more resistant to waterlogging and flooding among all studied poplar clone stecklings.