Abstract: An experiment was conducted in an artificial climate chamber to study the growth and physiological characteristics of switchgrass (Panicum virgatum) seedlings exposed to 0, 50, 100, 150, and 200 mmol·L^-1 of NaCl solutions. With the increasing concentration of the NaCl, the seedling growth was obviously inhibited. The plant height decreased, leaves became smaller, photosynthetic leaf area and net photosynthetic rate reduced, and dry matter accumulation decreased gnificantly, presenting the general traits of glycophyte. Meanwhile, the seedlings also showed relatively high salt tolerance. After exposed to 200 mmol·L^-1 of NaCl for 30- ays, the seedlings still survived, with the green leaf area per plant and net photosynthetic rate being  491.9 cm² and 0.93 μmol CO₂·m^-2·s·^-1, respectively. In this experiment,the salt tolerance threshold forP. virgatum was 178.6 mmol·L^-1 when taking 50 % drop in biomass as the standard.