In this experiment, we took the cuttings of two-year-old C. bungei tree (C.bungei No.1 and 008-1) as materials, and used pot experiment to analyze the growth and physiological changes of C.bungei tree seedlings under salt stress (0.5% NaCl). The alleviating effects of different concentrations of ABA (15, 25, 35 mg/L) on salt-stressed (30 d) C.bungei seedlings and their physiological and biochemical characteristics were analyzed, so as to explore the appropriate concentration of ABA for the growth of C.bungei seedlings under severe salt stress, and to provide theoretical basis for enhancing the salt-alkali tolerance of C.bungei and improving the utilization of saline-alkali land. The results showed as follows: (1) Under 0.5% NaCl stress, the seedling leaves of the two cultivars showed different degrees of salt damage symptoms, and the salt damage symptoms of the leaves of ‘C.bungei No.1’ were more serious than ‘008-1’. As the stress time increased, the relative electrical conductivity (REC) of the seedlings of the two cultivars increased first and then decreased, chlorophyll (Chl) and relative water content (RWC) decreased, and the activities of soluble sugar (SS), soluble protein (SP), proline (Pro) and superoxide dismutase (SOD) increased first and then decreased. However, the REC of ‘008-1’ was significantly lower than that of ‘C.bungei No.1’, and the Chl, RWC, SS, SP, Pro and SOD of ‘008-1’ were significantly higher than that of ‘C.bungei No.1’, indicating that ‘008-1’ had stronger salt tolerance than ‘C.bungei No.1’. (2) The seedling height of C.bungei ‘008-1’ was significantly increased and the new leaves germinated in advance under salt stress, which indicated that exogenous ABA could alleviate the effects of salt stress on the growth of C.bungei to a certain extent. ABA treatment decreased the REC of C.bungei ‘008-1’ seedlings under salt stress, and increased contents the of Chl, RWC and activities SS, SP, Pro, SOD, peroxidase (POD) and catalase (CAT). It promoted the accumulation of endogenous hormone auxin (IAA), abscisic acid (ABA), gibberellin (GA₃) and zeatin nucleoside (ZR). The results showed that the salt-tolerance of ‘008-1’ was stronger. Exogenous ABA spraying with appropriate concentration could alleviate the effects of salt stress on the growth of C.bungei seedlings, reduce the permeability of cell membrane in seedling leaves, promote the accumulation of osmotic regulatory substances in seedlings, enhance osmotic regulation ability, and improve the antioxidant enzyme activities, and promote the regulation of endogenous hormone contents in plants of seedlings under salt stress, thus improve the salt-tolerance of C.bungei seedlings. 25 mg/L ABA treatment had the best effect.