Sweet sorghum（Sorghum biocolor（L.） Moench） is one of the leading candidates for cleaner energycrops, and it is high tolerant to salt. Therefore we could plant sweet sorghum for bioenergy production in the sali-nized lands which is unavailable to other crops. In the present paper a sensitive genotype Tianganshushu（TGSS）and a tolerant variety M81E were chosen to study the effect of NaCl stress on seed germination and seedling growthof sweet sorghum. The results showed that seed germination rate and germination energy decreased significantly by 80 mmol/L NaCl solution and 160 mmol/L NaCl solution treatment, but no significant difference was found betweenthe two concentration. The reduction of germination rate and germination energy of M81E were larger than those ofTGSS, indicating M81E was more sensitive to NaCl than TGSS during seed germination. Root and shoot growth weresignificantly affected by 160 mmol/L NaCl solution treatment. Root length was more sensitive to NaCl than root freshweight. Similar response was found in fresh weight of shoot, total fresh weight of plant, leaf area, and TGSS was moresensitive to NaCl than M81E for its greater reduction in these indexes. According to the R/S, salinity stress affectedshoot growth much more than root growth.