[Objective] This study aimed to investigate the effects of space mutation on the activities of protective enzymes in different strains of Cichorium intybus L. and provide theoretical basis for screening drought-tolerant plants in southern karst area. [Method] C. intybus seeds were sent into outer space by ＇Shijian No.8＇ seed- breeding satellite. The new strains and original variety of C. intybus L. were used as experimental materials to determine the activities of catalase （CAT）, peroxidase （POD）, superoxide dismutase （SOD）, and malondialdehyde （MDA） content. [Result] The results showed that MDA content in PA-82, Puna chicory and PA-43 increased gradually with the increase of water stress duration, which was enhanced by 0.575, 0.72 and 0.844 μmol/g respectively at 12 days. In addition, the activities of SOD, POD and CAT increased rapidly; at 9 days, the activities of SOD in PA-82, Puna chicory and PA-43 were enhanced by 878.9, 809.2 and 711.1 U/g, with the increas- ing range of 139.1%, 136.7% and 121.1%, respectively; the activities of POD were enhanced by 4 397, 3 754 and 2 767 U/（g ·min）, with the increasing range of 265.84%, 257.65% and 204.06%, respectively; the activities of CAT were enhanced by 402.1, 277.1 and 170.9 KU/L, with the increasing range of 73.08%, 39.69% and 26.20%, respectively; subsequently, the activities of these three protective enzymes were reduced significantly; at 12 days, the activities of SOD in PA-82, Puna chicory and PA-43 were reduced to 1206.5, 1144.7 and 1108.6 U/g, respectively; the activi- ties of POD were reduced to 3 145, 2 876 and 2 753 U/（g·min） , respectively; the activities of CAT were reduced to 587.2, 698.1 and 584.1 KU/L, respectively. [Con- clusion] According to the results of comprehensive evaluation, drought resistance in three C. intybus varieties exhibited a descending order of PA-82 〉 Puna chicory 〉 PA-43.
