Firm competition has become a major issue in the strategy research since Porter introduced the “Competitive Strategy” in 1980. Porter suggested that strategy is depended on the industry competitive environment through a series study (Porter, 1980, 1985, 1990). He brought out several well-known concept and analysis tools, including Five Force Analysis, Generic Strategiesand ValueChain etc. However,Porter’s theory was challenged by the dynamic competition concept and hard to apply in the practical. In this study, seven statements from Porter’s theory had been integrated and three of them were debated and proved. We classified and discussed the rest four indeterminatestatements from the previous literatue.Two corporation of the bicycle industry were taken into this evidence analysis study, namely GIANT and MERIDA. By using a Case-Oriented Comparative Method combined with dynamic competition concept, we aimed to answer the four indeterminate statement of the Porter’s theory. Consequently, the improved practical capability of Porter’s theory is expected. The four indeterminate statementswere listed: (1) Strategic group with a different environment would conduct different achievement of corporation. However, the corporation is able to transfer to the different competition groups with time passing or resource integrating. Therefore, the corporation should decide a strategy according to the current resource and the scale of corporation. (2) The strategy of a corporation was depended on the different management period and environment. In the beginning, corporation which was restricted to the resource and positioning was suggested to choose either low-cost leadership or differentiation strategy. However, corporation could mix the strategy after well-developed. (3) The uniqueness of strategy positioning and the internal resource was mutually complementary and became an advantage of corporation competition. For example, the specific positioning would generate identical resources;on the other hand, the new resource would feedback to the corporation and generated a new positioning. (4) The complementation of corporation strategy and competitive strategy should be considered while generating a competitive strategy. The implementation of competitive strategy should be taken into the business scope.