In constructing Digital Elevation Model (DEM) from image pairs

often the elevation data of point cannot be directly recoverd

due to the limitation of the mapping algorithm adopted and the mutual hiding of the terrain itself. Therefore it is very important to construct a dense terrain model from these sparse data by means of interpolation. In this paper

based on the fractal features of natural terrain

a Spacial Polyhedron Model Deformation algorithm is presented

which can generate realistic dense terrain model from sparse points that are irregularly distributed. The experimental results are satisfactory.