Abstract: The effects of different concentrations of calcium chloride (5, 10, 15 mmol·L⁻¹) on the physiological characteristics of Prunus triloba seedlings under salt stress (0.4% sodium chloride) were studied with P. triloba Lindl. current year seedlings as experimental materials. The results showed that: (1) The SOD and POD activities in P. triloba seedlings were increased under salt stress, and the activities of this two protective enzymes were significantly increased in 10 mmol·L⁻¹ calcium chloride treatment under salt stress, and the 15 mmol·L⁻¹ and 10 mmol·L⁻¹ treatments had no significant difference. (2) The chlorophyll content of P. triloba seedlings was decreased under salt stress, and 5 mmol·L⁻¹ calcium chloride treatment did not significantly affected the chlorophyll content of P. triloba seedlings under salt stress, but 10 mmol·L⁻¹ treatment significantly increased the chlorophyll content of P. triloba seedlings under salt stress. (3) Both 10mmol·L⁻¹ and 15 mmol·L⁻¹ calcium chloride treatment could significantly increase the net photosynthetic rate of P. triloba seedlings, but 5 mmol·L−1 treatment had no significant effect on the net photosynthetic rate of P. triloba seedlings under salt stress; (4) The activities of sucrose phosphate synthase and sucrose synthase in P. triloba seedlings leaves were increased under salt stress, but the activities of this two enzymes in P. triloba seedlings were significantly reduced in 10 mmol·L⁻¹ calcium chloride treatment under salt stress. According to comprehensive analysis, 10 mmol·L⁻¹ was the suitable concentration of calcium chloride to alleviate salt stress of P. triloba seedlings.