Abstract: It is an important issue to explore how the path of ecological co-prosperity can promote urban-rural co-prosperity. The construction of national forest city is an policy to promote the urban-rural integration and realize rural revitalization, which is in line with the common demands of urban and rural people, and it is of great practical significance to pay attention to the policy impact of national forest city construction on the urban-rural integration from the perspective of institutional assessment. Based on the dynamic panel data at the level of 269 cities, the impact of national forest city creation on urban-rural integration and its mechanism are systematically examined by using difference-in-difference model (DID), propensity score matching difference-in-difference model (PSM-DID), panel quartile model, mediation effect model and threshold effect model. The results show that the forest city construction can effectively promote urban-rural integration, and the above conclusion still hold after the endogeneity problem is dealt with and the robustness test is conducted. The results of the mechanism analysis show that the forest city construction indirectly promotes urban-rural integration by promoting air pollution control and incentivizing green technology innovation. The results of heterogeneity analysis show that there is a marginal incremental effect of the positive impact of forest city construction on urban-rural integration as the development level of urban-rural integration increases. In addition, the positive impact of forest city construction on urban-rural integration is more significant in eastern cities, non-resource cities and key cities for environmental protection. The threshold effect indicates that the impacts of national forest city creation on urban-rural integration have nonlinear incremental characteristic. When the intensity of environmental regulation and industrial structure transformation cross the threshold, the positive impact of forest city construction on urban-rural integration increases significantly. Accordingly, we should build a new model of “urban-rural synergistic development” for national forest city creation according to local conditions, strengthen urban-rural air pollution prevention, and promote urban-rural integration with green technology as a new engine.