Constructing a tax system with international competitiveness is one of the main characteristics of Hainan Free Trade Port. Since the ‘Overall Plan’ clarified the tax system principles of Hainan Free Trade Port in 2020，the tax system construction has followed the ‘top-level design，small steps fast run’ model，and a complete tax system framework has been constructed，continuously optimizing the tax policy system. With the upcoming full island customs closure，the tax system construction of Hainan Free Trade Port was further optimized and improved in 2023. According to the economic development of Hainan，the tax exemption policy for leaving the island was optimized in real time，the scope of application for ‘zero tariff’ on transportation vehicles and yachts was expanded，the encouraged industry catalog was revised，and the tax policy for pilot imports of aircraft and ships was introduced，significantly enhancing the convenience of investment and trade in Hainan. At the same time，improving the tax system of Hainan Free Trade Port also faces some challenges，such as frequent adjustments to tax policies，preferential policies focused on key industries that are not conducive to balanced industrial development，and an urgent need to improve the income tax system. To this end，it is necessary to further improve the tax system framework，optimize corporate income tax policies to promote fairness and efficiency，strengthen the collection and management mechanism to prevent risks；at the same time，considering the upcoming customs closure，it is necessary to release the linkage policy between sales tax and value-added tax as soon as possible，introduce the sales tax system，and provide basic and safeguard institutional support for the opening up and high-quality development of Hainan Free Trade Port.