Abstract: In order to enhance the level of the local manufacturing industry, the developed countries put forward the strategy of re-industrialization now. Thus, Chinese government also puts forward "Made in China 2025" plan, and proposes policy guidance to promote the convergence of Internet technology and manufacturing. Therefore, in the context of industrial Internet, how to do strategic transformation for China's manufacturing enterprises is an extremely important issue. This research will use the embedded multi-case analysis method and choose Mengniu, Baoxiniao and Changhong three manufacturing enterprises as research objects. Through longitudinal analysis of the three enterprises' intelligent growth trajectory and strategic transformation process, and horizontal comparison of the basis, focus and path before the ecological strategy transformation of the three enterprises, this research will explore the path of ecological transformation of Chinese manufacturing enterprises under the background of industrial internet.