IT capability based on RBV cannot provide firms with durative competitive advantage. IT capability consists of basic IT capability and critical IT capability. Meaning alignment of IT capability is that firm will select optimal basic IT capability compatibility according to difference of critical IT capability between two firms. This paper used Stackelberg model to research alignment of IT capability factors based on consumer theory. When competitor selected higher compatibility to IT service standards, the incumbent firm should enlarge critical IT capability advantage, which enable it to achieve vertical differentiation competitive advantage; when competitor selected lower compatibility to IT service standards again and enhance its critical IT capability, the incumbent firm only keep its critical IT capability advantage, which can achieve competitive advantage. Two kinds of competitive can transform each other, which enable competitive advantage to be persistence and dynamic.