It has been reported that the membrane charge of amphoteric membranes such as inorganic membranes depends on the pH and the electrolyte in the bulk solution. To explain these phenomena, we have proposed the advanced amphoteric membrane (AAM) model where the effective membrane charge is determined by the dissociation of the amphoteric membrane material as well as by the selective adsorption of ions. We applied the AAM model to the alumina membranes and microporous glass membranes to characterize their membrane charges. It was concluded that the effective membrane charge of these membranes was determined by the dissociation of membrane material besides the selective adsorption of ions. It was also shown that the dependency of the effective membrane charge on the pH and the electrolyte was well explained by the AAM model.