This research investigated the growth response and Na+ and K+ absorption and accumulation in seedlings of four winter wheat genotypes under salt stress. The results showed that the water content, biomass, dry weight, and K+ concentration and accumulation of the seedlings decreased greatly under salt stress. In contrast, the concentration and accumulation of Na+ and Cl- in the seedlings increased. The Na+/K+ ratio in the seedlings increased as the salt concentration increased in the growth medium. There were differences in the concentration and accumulation of Na+ and Cl- among the wheat genotypes, which indicated that wheat roots had genotypic differences in total absorption of Na+, K+ and Cl-. Genotype NR9405 has a higher canopy temperature compared to the other genotypes. Under salt stress, it had a higher capacity for selective K+ uptake and lower Na+ uptake and translocation compared to the other genotypes. As a result, it had a higher cytosolic K+ concentration and a lower Na+/K+ ratio. It also had greater biomass production compared to the other genotypes. In contrast, genotype RB6 has a relatively low canopy temperature. Our results indicated that it had a lower capacity for K+ uptake and a higher capacity for Na+ accumulation compared to the other genotypes. This resulted in a higher Na+/K+ ratio and lower biomass production. Na+ entering the plant could function as an osmotica and adjust the osmosis potential and maintain the osmosis balance under low NaCl concentration. Excessive Na+ absorption is one of the main causes of plant injury and a reduction in growth under high salt stress. The ability to maintain a low cytosolic Na+ concentration and a small Na+/K+ ratio could be a major characteristic of salt tolerance in wheat.