Abstract: The physiological indices of leaves of three sweet potato cultivars: salt tolerant Xushu 18, salt mid tolerant Lizixiang and salt sensitive Shengli Baihao, under the 0,85,170,255 or 340mmol/L NaCl solution stress for 6d , were analysed The results showed that with the increase of NaCl concentration, the water potential(w)and relative water content (RWC)of sweet potato leaves gradually decreased, and photosynthetic rate(Pn), transpiration rate(Tr), efficiency of water application(WUE), stomatal conductance(Gs)and stomatal aperture also markedly declined Intercellular CO2 concentration(Ci) decreased under the low NaCl concentration stress, and with the increase of NaCl concentration , Ci gradually rised , and endogenous ABA content also increased Under salt stress, above physiological indices varied in different cultivars It means that NaCl concentration was extremely negatively correlated with RWC,w, Pn, Tr and Gs Under the of NaCl solutions stress, the NaCl concentration was positively correlated with Ci and extremely positively correlated with endogenous ABA contents, while ABA, RWC and w were extremely negatively correlated with endogenous ABA, but extremely positively correlated with Pn, Tr and Gs Endogenous ABA was extremely negatively correlated with Pn, Tr and Gs