By means of analyzing the content of proline and soluble sugar,leaves-washing technology,X-ray analysis and scanning electron microscope(SEM),the change of proline and soluble sugar and the composing of washings from oats leaves were analyzed,and superficial structure of leaves were observed under saline-alkali stress.The results revealed that the content of proline and soluble sugar increased with increasing salinity in both breeds,the washings from oats leaves of saline-alkali stress were comprised Cl-,Na ,K ,HCO-3,Mg2 and Ca2 and none of CO2-3 and SO2-4.The quantities of Cl-,Na and K of treated leaves washings were most significant higher than control.The quantities of HCO-3 and Mg2 of treated leaves washings were significant higher than control.There was none significant difference to the quantity of Ca2 between treated and control.There were large numbers of salt crystals on the stomata,the resistant mechanism in oats to saline-alkali stress is discharging salt by stomata.