To the parties of an Investor-State dispute, not only resolving the dispute but ensuring continued operation of the involved investment project can be of importance. In this regard, mediation would provide solutions based on parties' interests and, thus, contribute significantly to an on-going cooperative relationship. An increasing awareness of Investor-State mediation's value appeared in the past decade. Particularly, China and the EU have respectively shown their interest in using mediation as a step in investment dispute resolution. As such, in the context of a prospective China-EU Bilateral Investment Treaty, it is necessary to give serious consideration to the design of such an Investor-State mediation mechanism, especially the problematic issues that could stand in the way of parties' treaty negotiations. A cautiously designed mediation mechanism in this treaty will be beneficial to successful investment dispute resolution between China and the Eli, and provide inspirations to other investors and States.