Industrial collaborative agglomeration is an internal requirement and an important way to build a modern industrial system and a new development pattern, as well as an effective way to promote the high-quality development of the regional economy. However, the existing literature is not in-depth on the mechanism of industrial collaborative agglomeration affecting the high-quality economic development of the region, and there is no consensus on the empirical analysis of the nonlinear relationship between the two. The evaluation method for high-quality economic development in the empirical test also needs to be improved. This paper argues that industrial collaborative agglomeration will generate positive externalities such as specialized division of labor, economies of scale, factor sharing, and knowledge spillovers, thereby promoting the high-quality development of the regional economy. However, the congestion effect and competition effect caused by excessive agglomeration will also damage the quality of economic development. Therefore, there is an inverted U-shaped nonlinear relationship between industrial collaborative agglomeration and high-quality economic development, and it shows regional heterogeneity due to differences in regional economic development levels and factor endowments. Meanwhile, high-level industrial collaborative agglomeration (such as the collaborative agglomeration of high-tech intensive industry) has a more significant role in promoting the high-quality development of the regional economy; industrial collaborative agglomeration can promote high-quality economic development by improving the efficiency of regional innovation, and the improvement of regional human capital levels will strengthen the promotion effect of industrial collaborative agglomeration on high-quality economic development. Using the panel data of 30 sample provinces from 2004 to 2020 and based on five dimensions including economic growth efficiency, industrial structure optimization, economic growth stability, welfare improvement and income distribution, resource utilization and ecological environment, the high-quality development level of the regional economy is evaluated and the impact of the collaborative agglomeration of producer services and manufacturing on the high-quality economic development is analyzed. The results show that industrial collaborative agglomeration promotes the high-quality development of regional economy on the whole, but there is an inverted U-shaped relationship between them. It also shows the regional heterogeneity of “significant promotion in the eastern region, insignificant impact in the central region, and a U-shaped relationship in the western region” and the industry heterogeneity of “significant promotion in the collaborative agglomeration of high-technology intensive industries, insignificant influence in the collaborative agglomeration of low-technology intensive industries”; regional innovation efficiency has a mediating effect on the promotion of high-quality economic development by industrial collaborative agglomeration, but the promoting effect of innovation efficiency by industrial collaborative agglomeration is not significant during the sample period; the improvement of regional human capital level will strengthen the promotion effect of high-quality economic development of industrial collaborative agglomeration, and play a regulating role in its innovation efficiency path. Compared with the existing literature, on the basis of optimizing the evaluation indicators of high-quality economic development, this paper empirically tests the nonlinear relationship between industrial collaborative agglomeration affecting high-quality economic development and its regional and industry heterogeneity, explores the intermediary mechanism of innovation efficiency and the regulating role of human capital, and deepens and expands relevant theoretical research and empirical analysis. Based on the research conclusions of this paper, we should pay attention to the reasonable boundaries of industrial collaborative agglomeration, focus on supporting high-level industrial collaborative agglomeration, improve the quality of industrial collaborative agglomeration, strengthen the accumulation of human capital and its matching with industrial integration and development, and effectively promote the high-quality development of regional economy through appropriate industrial collaborative agglomeration according to local conditions.