With the rapid development of the society, the public's demand for spiritual culture and the need for cultural relic’s appreciation are also rising. Therefore, it is absolutely necessary to change the traditional way of tourism with science and technology to shunt the passenger volume in the world cultural heritage scenic spot. With flow theory and VR technology, tourists can interact with the scenic spot from all aspects without actually reaching the destination for personal exploration. In addition, VR technology can be used to replan the scenic spot itinerary according to the pain points thereof. Taking the immersive virtual tourism products of Dunhuang Mogao Grottoes as the carrier, the work analyzes the specific process of tourists entering the state of flow, and puts forward specific design principles and key contents. The immersive virtual tourism products based on the flow theory are used to overcome the superficiality of the current digital Dunhuang Mogao Grottoes. Concrete measures used to guide the users to experience the flow are obtained and the clear targeted itinerary is sorted out to give users more enjoyable experience, thus proving the feasibility of the immersive VR tourism product design.