The MFN clause is the basis of WTO and the Article 24 of GATT，as the main exception thereof，provides the justification base for the establishment of FTA.Due to the causes in the negotiation history of GATT and WTO，Article 24 of GATT is not clear.The proliferation and development of FTA sha smade themselves become the international economic legal system paralleling WTO system.It is necessary for China to set up our FTAs system and rules according to our trading and economic condition.