The highest form of economic integration is called the economic union which is characterized by integration of the domestic policies of its members in respect of economy, finance, etc. in addition to absence of trade barriers, practice of common external policy and free production factor mobility. The members of an economic union are required not only to harmonize their taxation, government expenditures, industry policies, etc., but also use the same currency.
一体化程度最高的是经济联盟。其成员不仅清除贸易壁垒，实行统一的对外经贸政策，实现生产要素自由流动，而且统一协调各国在经济、金融等领域的国内政策。经济联盟的成员不仅要在税收、政府开支、产业政策等方面保持一致，而且还要使用同一的货币。
