1. As a consequence, principle of tariff concession arises out of the practice of liberalization.

2. Multilateral Tariff Negotiation and Multilateral Tariff Concession - Are the forming of custom unions always increases members'welfare?

3. Thus, in - depth research on the theory and practice of tariff concession is great significative in reality.

4. In addition, the article explains Regional Cooperative System's influence on Tariff Concession and the consideration about Regional Cooperative System.

5. This paper is divided into four chapters to research into the system of tariff concession.

6. After 8 Rounds of negotiations of GATT, free-trade and the tariff concession become the trend of international trade.