The invention relates to an interaction-based building point cloud model texture mapping method and a device, which belongs to the technical field of computer visual processing. In view of exterior outline features of a modern urban building, on the basis of reconstructing a space corresponding relationship between each three-dimensional point in the point cloud model and a corresponding pixel point in an image used for restoring the current space point, quick automatic faceting and texture mapping of the building model can be realized in the condition of simply and interactively demarcating each structural inflection point. According to the method, removal of noise points in the point cloud model is firstly carried out, corner points of the wall surface structure of the point cloud model through interaction with a user are then acquired, the best matching image of the wall surface is obtained through matching and selecting according to the selected corner points, a point cloud model wall surface is obtained through space plane fitting, and wall surface texture in the best matching image is mapped to the point cloud model wall surface. Compared with the prior art, the whole structure of the building can be quickly reconstructed, and the whole effects of the reconstructed result can meet daily needs.