Four ornamental species were planted in pots as the experimental material.They respectively are:Photinia fraseri,Buxus sinica(Rehd.et Wils.) Cheng var.parvifolia M.Cheng,Ligustrum×vicaryi Hort.and Euonymus japonicus Thunb.Natural drought-rehydration treatment was carried out in greenhouses.Physiological indicators of plants under drought stress and nature watering were determined,such as superoxide anion production rate,malondialdehyde(MDA),activities of superoxide dismutase(SOD),peroxidase(POD) as well as hydrogen peroxide enzyme(CAT).Investigating the generation of active oxygen and its enzymatic elimination process under drought stress and its recovery after rehydration will help us understand plant adaptation strategies to adversity and provide theoretical guidance for the scientific management of ornamental plants.The results showed that:(1)Under nature drought process,O^-·₂ generating rates of P.fraseri increased after shortly declined,while B.sinica var.parvifolia,Ligustrum×vicaryi and E.japonicus declined after shortly rising.(2)MDA content increased in P.fraseri and B.sinica var.parvifolia with little change in Ligustrum×vicaryi and Euonymus japonicus.(3)SOD activity of all the four species increases,while CAT activity declined after firstly increased.No trends were found about POD activity.(4)After rehydration,generation rates of O^-·₂ and MDA content of all the 4 species declined.SOD activity of B.sinica var.parvifolia,Ligustrum×vicaryi and E.japonicus increased while P.fraseri declined to control levels.CAT activity of Ligustrum×vicaryi increased,while all the other 3 species declined.As the POD activity,B.sinica increases with all the other 3 species declined.SOD and CAT activity promoted the elimination at first in P.fraseri.Different pathways for eliminating activated oxygen exist in the 4 ornamental plants.Subordinate function was used to rank their drought tolerance and the order was:B.sinica var.parvifolia＞Ligustrum×vicaryi＞E.japonicus＞P.fraseri.