To determine the physiological mechanism of mitigative effects of salicylic acid on salt-stressed Camptotheca acuminata seedlings, under the control of 0.5% NaCl stress, 4 treatments were set up: T₁（0.5% NaCl+60 mg/L SA foliar spray）, T₂（0.5% NaCl+60 mg/L SA root irrigation）, T₃（0.5% NaCl+120 mg/L SA foliar spray） and T₄（0.5% NaCl+120 mg/L SA root irrigation）. Through the comparison of Camptotheca acuminata seedlings' antioxidant enzyme activity, soluble protein content, MDA content as well as dry weight, we found that the mitigative effects of 60 mg/L SA was best, and the result of foliar spraying was better than that of root irrigating. Under the treatment of 60 mg/L SA foliar spraying, activity of protective enzymes in leaves of Camptotheca acuminata seedlings and content of osmotic adjustment substances increased significantly, MDA content decreased significantly, the dry weights of seedlings were higher than those of control significantly. This showed that application of salicylic acid at suitable concentration could enhance antioxidant enzyme activity, increase the content of osmotic adjustment sub-stances, thus protecting the integrity of the photosynthetic membrane, increasing cell water retention capacity, and ultimately promoting the growth of seedlings under salt stress. By studying the physiological mechanism of mitigative effects of salicylic acid on salt-stressed Camptotheca acuminata seedlings, theoretical basis was provided forsalt tolerance cultivation of Camptotheca acuminata.