In the immersive theater, the innovation of stage design is one of the reasons for the great success of the performance.  Stage design is to bring ordinary materials to the stage and redefine them through artistic creation, so that the audience can have a new aesthetic experience. Traditional theater stage design uses material materials to create a realistic space. With the development of technology in the digital age, the concept of “Mixed Reality” has been extended to stage design, allowing it to get rid of relying only on material materials. Mixed reality technology plays a significant role in the digital technology field by seamlessly integrating computer-generated virtual objects and scenes into the real world to create unique visual experiences. This paper proposes a heterotopia stage space construction technology based on Mixed Reality. It aims to study how to put virtual information into the real world by way of Mixed Reality in order to make dancers interact with a real virtual space. Then, taking as an example the dance drama Deep Weather – designed and produced by the author – this paper introduces the application of Mixed Reality technology in immersive theater, and focuses on the function and operation principle of the technology module. Finally, it summarizes a set of design principles of immersive theater construction technology based on Mixed Reality, including surprise, connecting physical space, aesthetics, facilitating actions, iteration and extension, and technicality