The dispute settlement mechanism of The United Nations Convention on the law of the sea is mandatory on the whole. The Convention establishes a sort of multiple heterogeneous mandatory jurisdictions, including judiciary jurisdiction, arbitration jurisdiction and auxiliary jurisdiction, and frames a kind of multiple mandatory processes in sequence, including pre-procedure, identification procedure, preliminary procedure and adjudication procedure. Facing Philippines’ strong push of the international arbitration unilaterally concerning Sino-Philippine South China Sea disputes, we can base ourselves on the multiple heterogeneous and sequential attributes of the Convention’s Mandatory Dispute Settlement Mechanism and let it serve us to make a clear justification for China’s “Double No” position and seek for the strategy and plan to maintain China’s sovereignty from the perspective of international law and thus provide a precautionary justification for China’s future position to the similar erosions to China’s sovereignty to win the support and understanding of the international community on China’s positions. We should use the preliminary procedure and adhere to the pre-procedure to make our objective stance to the arbitral tribunal’s acceptance of the case, use the rationae materiae and the issue of validity in time to explain why we assert that the arbitral tribunal has no jurisdiction to the case and use its award’s attribute to set aside the possible adverse ruling to maintain the state sovereignty.