Since the Maffezini case, debates upon the application of the Most-Favored-Nation (MFN) clause have never stopped. Research from the perspective of the Shanghai Cooperation Organization (SCO) can test the way for further advancement of this issue. The analysis on the international investment arbitration cases involving the SCO states may shed some light on the crucial point on dispute. At present, the bilateral investment treaties (BIT) between China and other states of the SCO are in an urgent need of renewal in order to meet the interests of deepening investment cooperation. Problems of fragmentation of the interpretation method and of unpredictability of the interpretation conclusion of the MFN clauses manifested in international investment disputes involving SCO states will provide concrete preventative suggestions on the updating of the wording of MFN clauses. Under SCO framework, the multilateral effect of the MFN clause can play a model role for other regional integration organizations to build an integrated and multilateral investment treatment system in the fragmented and bilateralism-based framework of international investment law, and in fact promote investment facilitation for regional organizations.