Abstract: Both high temperature and salt stress resulted in electrolyte leakage from Azolla fronds,and the amount of the leakage was increased with the increase of damaged degree. Under 45℃ high tem-perature,the leakage conductivity showed linar regression with the mortality of Azolla stem apex. In comparison of mortality of stem apex and relative leaking rate L(%)among different Azolla species treated at 41.5℃ in closed and at 45℃ in open water bath,L(%)could reflect the heat tolerance of tested Azolla species. Similarly,under the salt stress,electrolyte leakage accelerated with the incresae of salt concentration,and L(%)also has the same trend to reflect salt tolerance among Azolla species. Under 39℃C,Azolla has no significant accumulation of free proline which also showed on regu-lar variation within the temperature range which is 10℃ higher than the normal.However,in 45℃ water bath,free proline decreased with the prolonging of the treating time. Under the salt stress,free proline accumulated with the increase of salt content,and the more rapid accumulation of one species implied the more suscepitible of the species to salt stress.