A quasi-natural experiment was designed based on the Innovative Industrial Cluster Construction Project launched by the Ministry of Science and Technology in 2011, using panel data of Chinese cities from 2009 to 2020 and the progressive difference-in-differences model and the spatial difference-in-differences model, how the policy of "promoting construction by clustering" in national high-tech zones affects the high quality development level of their local urban agglomerations was empirically analyzed. The research shows that the innovative industrial cluster policy launched by the National high-tech zones can significantly promote the high-quality development of urban agglomerations, which is still valid after a series of robustness tests. In addition, the study after the differentiation of policy levels proves that the incentive effect of the pilot construction policy of innovative industrial clusters on the high-quality development of urban agglomerations is significantly stronger than that of the pilot cultivation policy of innovative industrial clusters. The results of the mechanism test confirm that the policy of "promoting construction by clusters" is used for the high-quality development of urban clusters through the innovation effect of central cities and the technology complementary effect of "center-periphery" cities. The empirical analysis can provide theoretical and practical basis for the institutional construction of national high-tech zones and the reform of industrial policy system.