A pH-sensitive PAA-co-octylphenyl polyoxyethylene methacrylate hydrogel[P(AA-co-C8PhEO10Mac)] was synthesized by free radical crosslinking polymerization, Swelling property, swelling and deswelling kinetics of the hydrogels in different pH media werestudied and hydrogel microstructures were investigated by means of scanning electron microscopy(SEM). L-ascorbic acid was chosen as a model drug and the controlled-release properties of hydrogels were pilot studied. The results showed that the P(AA-co-C8PhEO10Mac) hydrogel has a porous structure, both the rapid swelling and deswelling rate, good pH sensitivity characteristics; The swelling ratios of the gels in stimulated intestinal ?uids (SIF, pH=7.4) were higher than those in stimulated gastric ?uids (SGF, pH=1.4).With an increase of the content of acrylic acid, the swelling ratios of gels increased first and then decreased.The inhibitory effects of C8PhEO10Mac on escherichia coli and saccharomyces cerevisiae were sthdied, the results indicate that C8PhEO10Mac has no effect on them in the 10~50mmol/L test level.