The implementation of a new open economic system in China’s characteristic free trade ports urgently requires innovative legal guarantees for high-level openness and high-quality development. The exercise of the legislative power of free trade ports not only requires innovation in the content system of free trade port regulations, but also in the legislative path of free trade ports. This fully demonstrates the positive interactive relationship between the reform and opening up of free trade ports and the legal protection of legislative innovation, especially highlighting the novelty of the innovation in the exercise path of free trade port legislative power and the construction of free trade port regulatory system. The regulation and adjustment of the Free Trade Port Law, as well as the legislative authorization of the Free Trade Port, have become innovative channels for exercising the legislative power of the Free Trade Port, promoting the expansion of new content in the legislative power of the Free Trade Port. The regulation of free trade port law requires benchmarking with international economic and trade rules. The free trade port regulation focuses on areas with more practicality and pioneering applicability. The exercise of the legislative power of free trade ports not only focuses on the institutional openness of the content of free trade port regulations, but also focuses on promoting high-level openness and high-quality development through legislative content. It also emphasizes the coordinated promotion of the legislative supervision mechanism that integrates the constitutionality of free trade port regulations with reform and innovation. Hainan needs to adapt and create legislation, follow legislative authorization, and become a regulatory path for the exercise of legislative power in the Free Trade Port. It is also necessary to accelerate the implementation of customs closure operations in legislation and regulatory adjustments, ensuring that the Free Trade Port expands institutional openness and integrates into the international high-level free trade network as a legal guarantee.