It is too complicated to acquire pipeline layout information in BIM software. Based on Unity3D, a method of double projection is proposed in this paper. Through the development and application of BIM cloud platform function module, the method of obtaining electromechanical pipeline layout information is optimized. By obtaining the vertex coordinates of the object and projecting the vertex coordinates twice, the distance between the vertices in the three-dimensional world can be calculated quickly and accurately according to the projected coordinates, and the pipeline information can be displayed dynamically on the terminal equipment through programming. By using this method, the information of pipeline layout can be achieved, which provides convenience for the consistency of site construction and design intention, and provide accurate information for prefabrication of pipe in factory.