Abstract: For China national unification, from the perspective of institutional economics, the efforts from the Chinese Mainland authority as well as ChineseTaiwan local authority, are to better the value of state sovereignty. The unification path can be Hong Kong Mode, Federalism Mode, Quasi U.K. Mode, German Mode, Direct War Mode, Purchasing War Mode, and Political Parties Democratic Competition Mode. The War Mode costs a lot and is not the best choice for cross-strait reunification. Hong Kong Mode costs less, but Taiwans current willingness to compromise is less. The Democratic Competition Mode would change the whole politics into the Western election politics, which could destroy Chinese Mainlands centralization, with gains as well as losses, while, it breaks through the Chinese Mainlands constitutional framework, from the comparison of the international and domestic forces between Chinese Mainland and Chinese Taiwan, the possibility is very low.