It is difficult to extract scattered point cloud feature lines directly due to its characteristic of mass and not topological. A contour generation algorithm for point cloud based on rapid prototyping is described. The approach is that point cloud layers to project onto the slice plane and transform to grid image. It establishes line data structure to extract contour by calculating the domain connectivity. The list of the straight line is adopted to establish connectivity to solve the multi-connected domain problem; the point cloud in cell is compressed to solve the data redundancy and uneven distribution. Experiments show that this method of the contour line generated is rapid and effective.