Abstract: 【Objective】 To study the effects of different concentrations of NaCl treatment on morphology and photosynthetic characteristics of leaves of Populus talassica × P. euphraticain the hope of providing theoretical basis for exploring the environmental response mechanism of P. talassica × P. euphratica salt. 【Methods】 Changes of growth indexes and photosynthetic characteristics of leaves of P. talassica × P. euphratica of different concentrations NaCl (0, 200, 250, 300, 350, 400 and 450 mmol/L) were determined and analyzed using potted P. talassica × P. euphratica as test material. 【Results】 The inhibition of leaf length of P. talassica × P. euphratica by environment of 200-450 mmol/L NaCl was obvious, 450 mmol/L NaCl environment significantly inhibited leaf width. The effect of 200-300 mmol/L NaCl environment on the net photosynthetic rate (Pn) of P. talassica × P. euphratica was not significant, and Pn decreased significantly in 400-450 mmol/L NaCl environment and in salt environment transpiration rate (Tr) and intercellular CO₂ concentration (Ci) showed a first increase and then a decrease. 【Conclusion】 P. talassica × P. euphratica euphratica can grow well in medium and low concentration salt environment (0-350 mmol/L NaCl), but the leaf shape is narrow and small under high concentration salt environment (400-450 mmol/L NaCl with high net photosynthetic rate and strong salt tolerance characteristics, which provides a reference for studying the response mechanism of stress in P. talassica × P. euphratica.