Different from the existent summarizing papers on customs union,the author discusses the western viewpoints on the trade effect of customs unions from three logically connected aspects:first,the interest source of customs union;second,the reasons for the formation of customs union;and third,the determination of optimal external tariffs.

The Impact of EU s Eastern Enlargement on Trade Between China and the EU——Based on the Analysis of The Trade Effect of Customs Unions;

As a significant phase of regional economy integration, CU(Custom Union Substantially abolishes all tariff barriers and other restrictions to trade between member states, although CU doesn't realize the maximum welfare, it does enhance the welfare level of the whole Custom Union area.

The German Customs Union (or Zollverein) established in 1834 was the first step towards the German unification in economic field.

The German Customs Union (or Zollverein) established in 1834 is one the most important factors for the progress of German industrialization.

It is important for China to have diversified FTA partner objectives in which the promotion of Sino-SACU FTA should be a priority.