Since the Fifth Plenary Session of the 18th CPC Central Committee put forward the five development concepts of "innovation, coordination, green, openness and sharing"for the first time, China has entered a new era of high-quality economic development, which has opened a new chapter in the paradigm of high-quality economic development in China. Driven by the new development concept, local governments at all levels have taken both measures of environmental regulation and green innovation to promote the high-quality development of urban economy, and explored the impact of environmental regulation and green innovation on the high-quality development of urban economy, in order to achieve a "double-win" situation of "green mountains and green hills" and "golden mountains and silver mountains" in China. In this paper, twelve major urban agglomerations are used as sample data from 2008 to 2020 in China, and the influence of environmental regulation and green innovation on the high-quality economic development of urban agglomerations is systematically investigated by constructing OLS linear regression model, threshold effect model and intermediary effect model. The results show that: ① Environmental regulation has a significant promotion effect on the high-quality economic development of urban agglomerations, and the environmental regulation of southern urban agglomerations has a stronger promotion effect on the high-quality economic development of urban agglomerations than that of northern urban agglomerations. In addition, in order to avoid the problem that the estimation results are biased by endogenous environmental regulation, the conclusion obtained by constructing the lagging phase of environmental regulation as a tool variable is basically consistent with the original model, which proves the robustness and reliability of the original model. ② The influence of environmental regulation on green innovation shows an L-shaped relationship, in which the environmental regulation of southern urban agglomerations has a greater inhibitory effect on green innovation than that of northern urban agglomerations, while its promoting effect is weaker than that of northern urban agglomerations. Overall, the environmental regulation of southern urban agglomerations has a greater relative influence on green innovation than that of northern urban agglomerations, which shows that under the background of high-quality development of "green mountains and green hills" and "golden mountains and silver mountains" in China, the national and northern and southern urban agglomerations are all affected by this macro-policy environment. ③Environmental regulation plays a significant role in promoting the high-quality development of urban agglomeration economy, which is partly realized through green innovation, and environmental regulation plays a leading role; In addition, the green innovation ability of northern urban agglomeration plays a greater role in high-quality economic development than that of southern urban agglomeration, which shows that green innovation plays an important role in promoting high-quality economic development of northern urban agglomeration. Since the 18th National Congress of the Communist Party of China, environmental regulation and green innovation have played a more and more significant role in promoting the high-quality economic development of urban agglomerations. To realize the beautiful long-cherished wish of high-quality economic development of "Jinshan Yinshan" and "Green Water Qingshan", we not only need local governments to make scientific policies according to the location of urban agglomerations, make reasonable policies according to the industrial structure, coordinate inter-city relations within urban agglomerations, and coordinate the coordinated development of regional economies, but also need to further adjust measures to local conditions, make policies according to local conditions, and strengthen environmental regulation policies in a reasonable and orderly manner under the top-level design and guidance of the central government.
