Using Virtual Reality technology to implement the protection of intangible cultural heritage is more and more relevant today. The purpose of this paper is to discuss the construction of virtual scenes with key techniques of virtual roaming based on Unity 3D. Different directions have been arranged and analyzed to explain it in detail, including some methods related to virtual scenes construction, such as terrain, vegetation, baking models as well as some techniques about virtual roaming, such as camera design, collisions and GUI design. Combined with the intangible cultural heritage protection project Within the Bamboo Forest, this paper discussed the fundamental interactive frameworks both indoors and outdoors of the virtual scenes, and summarized the approaches to the construction and procedures of interaction based on the virtual scenes from the research and practical experiences.