The properties and conformation of alkaline protease and papain in ethanol solutions were researched.The results showed that the optimum temperature of alkaline protease and papain in ethanol solutions were reduced with the increase of ethanol concentration.The range of temperature descent was 5~10℃.The optimum pH in ethanol solutions had little difference comparing with buffer solution.With the increase of ethanol concentration,the stability of alkaline protease and papain were affected.Especially,when the concentration of ethanol solutions was up to 60%,the stability of alkaline protease and papain decreased rapidly.The stability of papain was higher than alkaline protease in the same ethanol concentration and the half-life of papain was 21 times of alkaline protease in 60% ethanol.The Circular dichroism spectra of the protease in ethanol solutions showed that the secondary structure of alkaline protease and papain were altered seriously.The Fluorescence spectra of the protease ethanol solution indicated that the fluorescence intensity of alkaline protease and papain in ethanol solutions were both weakened.These results confirmed that in ethanol solution the tertiary structure of those protease were changed obviously.