Effect of pH on the morphology and the property of microcapsules encapsulating peppermint oil by coacervation as wall material was investigated.The principle of the effect of coacervates on the morphology of microcapsules was illustrated.The results showed that with the decrease of pH from 4.3 to 3.7,the composition and productivity of coacervates rarely changed.So the increase of particle size of spherical multinuclear microcapsules was the result from the decrease of electronic resistant power and the increase of gelling property for coacervates.When pH was blew 3.7,the morphology of microcapsules turned irregular and released plenty of gelatin from coacervate wall material.