After China officially announced the nine-dash line in 2009, it has made notable policy adjustments. The article analyzes China's policy regarding East Sea in the period 2009-2021 on four main aspects, including: legal stance, political relations with the claimants and related countries, and maritime governance implementation in the East Sea, and views and implementation of the solution to the dispute. In addition to the point of view in settling disputes by bilateral instead of multilateral way, which is not much different from the period before 2009, China, on the one hand, implements a two-sided foreign policy towards coastal countries, on the other hand, attempts to supplement the legal position based on unclear points in international law. In addition to promoting unilateral activities to enforce the governance of disputed waters, it notably applies internal laws, establishes administrative management units in the disputed areas.