This paper studies the application of AHP to the decision-making of internationalization of bank location. When do so, the criteria level can include economic integration, opportunities in the host Country, regulation and bank capacity of the host Country. But the decision of a bank is made by a group of people and the judgment on the relative importance of the factors which affect foreign banking is according to objective factors. Thus there are many possibilities that cause missing important factor and setting a judgment matrix with error. When there is error in AHP, the lowest level of ranking vector will be different but the optimal decision will be the same if some conditions are satisfied. If not, the bank may not make an optimal decision. But the bank can decrease the errors and make the decision close to the optimal by enhance the ability of decision making and the skill of using AHP.