Abstract: Nowadays, the 3D printing technology is a revolutionary emerging technology. It combines the traditional manufacturing technology with the digital manufacturing technology, making a distinctive innovation pattern. In this paper, setting two largest global 3D printing enterprises as research objects, this paper makes an exploratory case study about 3D printing enterprise innovation ecosystem based on value network, constituent elements, ecological niche identification and operation mechanism. Through the case study, it finds that the core of 3D printing enterprise innovation ecosystem is made up of 3D printing enterprises and 3D printing material enterprises, which dominate the collaborative innovation among each element in the system. Furthermore, users occupy a relatively high ecological niche in the system. In addition, 3D printing enterprise innovation ecosystem owns an open boundary. These conclusions remind 3D printing companies that they should pay attention to construct open innovation platform and enhance collaborative innovation with 3D material enterprises and users.