Soil salinity can limit plant growth and productivity. The cultivation of tolerant varieties is convenient and cost-effective for making good use of the saline soils.The sweet sorghum plant has a high tolerance for saline alkaline soils. The KF1210-3 and KF1210-4 early-maturity mutants of sweet sorghum were obtained via carbon ion irradiation. The study assesses the productivity of three sweet sorghum cultivars(KF1210-3, KF1210-4, and KFJTCK) which were grown in intermediate(4.6 d S m~(-1)) and high(11.9 d S m~(-1)) soil salinity. The sweet sorghum grown in the soil salinity of 4.6 d S m~(-1)produced 50.00–57.30 %greater fresh weight than that in the soil salinity of11.9 d S m~(-1), while the difference was not as obvious among the dry biomass of the three sweet sorghum cultivars. Moreover, the Brix degree of the sweet sorghum grown in the soil salinity of 11.9 d S m~(-1)was greater than that grown in the soil salinity of 4.6 d S m~(-1). The heavy ion irradiation experiment is of great significance in screening plant mutants, improving environmental conditions, and assessing the productivity. This process, in turn, aids in the understanding of the effects of the biochemical and physiological mechanisms of salt stress. The cultivation of tolerant varieties is convenient and cost-effective for making good use of the saline soils. The sweet sorghum plant has a high tolerance for saline alkaline soils. The KF1210-3 and KF1210-4 early-maturity mutants of sweet sorghum were obtained via carbon ion irradiation. The study assesses the productivity of three sweet sorghum cultivars (KF1210-3, KF1210-4, and KFJTCK) which were grown in intermediate (4.6 d S m -1 ) and high (11.9 d S m -1) soil salinity. The sweet sorghum grown in the soil salinity of 4.6 d S m -1 produced 50.00-57.30% greater fresh weight than that in the soil salinity of 11.9 d S m -1, while the difference was not as obvious among the dry biomass of the three sweet sorghum cultivars. Moreover, the Brix degree of the sweet sorghum grown in the soil salinity of 11.9 d S m ~ (-1) was greater than that grown in the soil salinity of 4.6 d S m -1. The heavy ion irradiation experiment is of gre at significance in screening plant mutants, improving environmental conditions, and assessing the productivity. This process, in turn, aids in the understanding of the effects of the biochemical and physiological mechanisms of salt stress.