As one of the modern transportation infrastructures, the demand of expressway construction keeps growing since China is now standing at a historical juncture of achieving the two centenaries′ goals. The ratio of tunnel in expressway construction is much higher in Yunnan province due to mountainous topography; traditional design method cannot satisfy the demands nowadays, therefore, BIM technology is introduced since it becomes a main direction in project design. Since tunnel in expressway looks like a flat ribbon geometrically, goes up and down spatially, presents cross-section differently, if architectural BIM method is directly applied, it actually doesn't work and doesn't acclimatize. "Revit+Dynamo" method is used in this article to solve the real 3D modeling of long spiral tunnel, which accumulates experience for future tunnel BIM modeling practice.