Abstract: In order to further study the salt- tolerance mechanism of Ipomoea batatas Lam, three cultivars,‘Xushu No 18’,‘Lizixiang’, and‘Shengli No 100’were used to investigate the physiological basis of salttolerance, and the effects after treated with Ca²⁺ were studied. The results showed that under salt stress, the contents of total N and Chl a, Chl b, DNA, RNA and RNA/DNA ratio in leaves were declined, free amino acid contents were increased, and praline was rapid accumulated. After treated with Ca²⁺ , Na⁺ in leaves were declined, ability of salt-tolerance was increased, injury of plasma membrane was delayed, kinds and activities of isoenzyme were increased, three cultivars showed the same. This research would be helpful to the further study of salt-tolerance mechanism of Ipomoea batatas Lam, and probably provides basic theory for its breeding and high-yield plantation.