【Objective】Studying the response of Salix variety to salt stress and the threshold of salt tolerance could provide reference for further research salt resistance mechanism and expansion of planting scale in saline-alkali land.【Method】The tissue culture plantlets of S. ×jiangsuensis‘J172’(‘J172’) were treated with NaCl 0, 50, 100, 150, 200 and 250 mmol/L for 10-20 days under in vitro culture. The changes of morphology, physiological indexes and antioxidant enzyme isozyme bands in ‘J172’ plantlets were studied.【Result】‘J172’ plantlets had certain salt tolerance, and its salt tolerance threshold was lower than 150 mmol/L NaCl, its growth was seriously damaged and even death under higher than 200 mmol/L NaCl. Under mild salt stress (50 mmol/L NaCl), the growth of ‘J172’ plantlets were not affected, and the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), proline and glutathione (GSH) were mildly increased, other indexes were no significant changes. Under moderate salt stress (100-150 mmol/L NaCl), the levels of chlorophyll (Chl) and soluble protein (SP) decreased slightly, while the levels of relative conductivity (REC), malondialdehyde (MDA) or H₂O₂ began to increase, and the levels of GSH and SOD, POD and CAT reached a high point, respectively, and the salt tolerance reached the highest at these treatment. However, at high salt stress (200-250 mmol/L NaCl), the contents of Chl, SP and GSH decreased sharply and reached the lowest point, while the levels of REC, MDA reached the highest point, respectively, and the levels of GSH and SOD, POD and CAT activities decreased significantly, indicating that ‘J172’ plantlets were subjected to severe oxidative stress. Salt stress also led to the significant enhancement of isoenzyme bands such as CuZnSOD in chloroplasts and cytoplasm, MnSOD in mitochondria as well as POD2, POD3 and POD4.【Conclusion】The ‘J172’ clones had certain salt-resistant ability and could be cultivated in salt-bearing areas lower than 150 mmol/L.