Abstract: To study the responses of Casuarinaceae equisetifolia defense enzymes to Ralstonia solanacearum, the contents of soluble protein and activities of peroxidas (POD), catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were measured after R.solanacearum inoculated on C.equisetifolia by the injured root inoculation of potted seedling method. The result showed that the activity of protective enzymes in C.equisetifolia had been changed significantly after inoculation and the activity of SOD, PPO and PAL showed a waved curve. However, the activity of CAT and POD were decreased and much lower than that in the control. In addition, the contents of soluble protein were increased, which were consistent with the changes of SOD, PPO and PAL activities. The results indicate that R.solanacearum may induce resistance by increasing the activities of SOD, PPO and PAL in C.equisetifolia leaves.