Based on the panel data of 32 large as well as medium-sized cities along the coast from 2006 to 2017, this paper uses a difference-in-differences model to quantitatively test the impact of the establishment of a free trade zone on opening degree． The research results show that, the establishment of the free trade zone has a significant positive impact on the promotion of opening degree． A comparative study based on the classification of the establishment time of the free trade zone found that, the promotion effect of the first and second batches of free trade zone are more obvious． However, the promotion effect of the third batch of free trade zone are not outstanding enough． After analysis, this shows that the innovation effect of the system in the free trade zone have a certain lag, that is, the longer the establishment, the more obvious the effect． The research in this paper provides a method for the evaluation of the effect of the free trade zone, and also provides a reference for further promoting the high-quality development of China’s free trade zone．
