A novel acrylic acid crosslinked chitosan membrane was prepared through a homogeneous solution reaction and its pervaporation separation properties of ethanol/water mixtures were investigated. The selectivity of chitosan membrane was remarkably improved by crosslinking in the separation of ethanol/water mixtures and it highly depends on the preparing conditions and increased with temperature increasing.When the ethanol in feed is above 50% (percentage by weight),the water in permeate is no less than 98%.