Abstract
Many developing countries use tax reform as a strategy to support national or regional development. China's tax reform of the Hainan Free Trade Port in 2025 serves this purpose. The reform replaces the existing VAT, consumption tax, vehicle purchase tax, urban maintenance and construction tax, and education fee ("four taxes and one fee") with a sales tax. Previous studies of tax structure reform have rarely addressed the economic impact of such a transition, and few sales tax studies have discussed the issue of optimal tax rates. To study the economic effects of the introduction of sales tax and to find the optimal tax rate, this paper uses the computable general equilibrium (CGE) model to conduct simulation analyses. It is found that the sales tax rate should be 17.16 % to keep the fiscal revenue of Hainan Province more or less unchanged after the 'four taxes and one fee' are simplified into sales tax. The total economic volume and sales tax rate show an inverted 'U' type relationship, the optimal sales tax rate is about 9.79 %, and the tax rate of GDP, investment, employment growth of 3.82 %, 0.35 %, 3.41 %, respectively, the manufacturing industry and other industries in most of the different degrees of growth. Therefore, we suggest that the average sales tax rate of Hainan Free Trade Port should be around 9.79 %.