The entry into force of RCEP and the lack of ISDS mechanism have led to a heated discussion on China, Australia and the ChAFTA. The most significant issue is the investment dispute settlement “joint control” mechanism under the ChAFTA. The mechanism balances the interest of the host country, investor and home country by handing over the identification right of public interest measures of the host country to both states. It also protects the regulatory autonomy of the host country and realizes the sustainable development goal of both states. There are two difficulties of the investment dispute settlement “joint control” mechanism under the ChAFTA,which are about both qualitative and quantitative aspects of public interest measures of the host country. In order to solve the problems, the state parties are supposed to analyze the measures of the host country from a dynamic and developmental perspective. Also, they should bring the preventive policies and behaviors of the host country into the scope of public interest measures. What’s more, they need to add the "necessary and appropriate" clause to it with reference to the principle of proportionality in administrative law and the customary international law. Finally, states parties are supposed to add the mechanism to RCEP.