Has China's Free Trade Zone policy expedited port production and development?

China's free trade zone (FTZ) policy satisfies China's objective demand to get geared to the economic globalization trend and forms an essential part of China's opening-up strategy, creating new opportunities for Chinese seaports. Seaport development is subject to its throughput and the import and export trade scale of the city where it's located, but the growth rates of the two are not synchronized. To identify the impacts of FTZ policies on China's free trade seaports, with port throughput and import and export trade scale of the city taken into consideration, this article selects four Chinese seaports, namely Shanghai Port, Tianjin Port, Guangzhou Port, and Fuzhou Port, which are located in the FTZ establishment earlier, and bases the study on the port throughputs and import and export trade volumes of their cities from 2000 to 2020 for empirical testing with the allometric growth model and linear scale factors. The results show that the impacts of FTZ policies exhibit differences from region to region. Specifically, the FTZ promotion policies have lagging impacts on Shanghai Port and Tianjin Port. The Guangdong Free Trade Zone's policies have a short-term continuous promoting impact on Guangzhou Port's production. In contrast, Fujian Free Trade Zone's policies are a strong stimulus to the development of Fuzhou Port. The empirical test about the FTZ policies' impacts on seaport development will provide a theoretical basis for figuring out the critical role of FTZ in promoting the high-quality development of seaports and boost the coordinated development of ports and urban economies.