The cuttings of Amur grape varieties (Zuoshaner) were treated with different concentrations of NaCl(0,0.1%,0.3%,0.5%),and chlorophyll fluorescence parameters of the cuttings were determined in 20th day after salt stress.The ultrastructure of the leaves were observed in 25th day under 0 (CK) and 0.3% NaCl treatments to study the mechanism of salt tolerance in Amur grape.The results showed that:(1)At middle salt level (0.3%) or high salt level (0.5%) the minimal fluorescence (F₀) increased significantly,while the photochemical efficiency (F_v/F_m),potential activities of PSⅡ(F_v/F₀),photochemical quenching coefficient (q_P),actual photochemical efficiency of PSⅡ(Φ_PSⅡ),non-photochemical quenching coefficient (NPQ) and electron transport rate (ETR) all decreased significantly under the two stress conditions.The results suggested that the reaction center of photosystem Ⅱand the electron transport at the acceptor side were probably damaged,and the capacity of lose excess excitation energy through the heat dissipation was decreased.(2)Compared with CK,the ultrastructure of chloroplast had significantly changed under moderate stress.The shape was shortened and round,big starch grain disappeared,plasmolysis was appeared apparently,grana and stroma lamella were obscured.The capsule was damaged or disintegrated and the plastoglobulus in chloroplast increased.The ultrastructural observation showed that the morphological structure of chloroplast was seriously damaged.（3）It was observed that mitochondrial cristae of Amur grape arranged in disorder and mitochondrial membrane were obscured or dissolved,but had no obvious fracture phenomena under salt stress.The results indicated that mitochondria was harmed lightly and it was relatively insensitive to NaCl compared with chloroplast.（4）The nuclear morphometry was changed under salt stress.The nuclear membrane was dissolved or disappeared,but not completely disintegrated and it revealed the damage of nuclear caused by salt stress.