Because of introduced cosurfactants,which are important parts in the systems,miniemulsion polymerization is a new kind of emulsion polymerization.Characteristics of the miniemulsion polymerization and functions of cosurfactants in the miniemulsion polymerization were described,the influences of cosurfactants on the miniemulsion polymerization were analyzed,and the defects of current cosurfactants were pointed out.The significance must be emphasized of developing various kinds of cosurfactants and functional cosurfactants.