This paper studies 3D surface integration from novel angle. The authors consider the construction to the multiple surface patches, not one surface, from the Gauss map. The algorithm takes as its input a 2D field of surface normal estimates, delivered, for instance, by a shape-from-shading or shape-from-texture procedure. The authors disintegrate the Gauss map into two functions by the spherical coordinates, and then borrow the ideas from routine image processing theory to filter the two functions and to segment the space surface into several subsurface, at last the authors use the integrability to recover the subsurface individually. The method only exploits the general techniques in image processing, but can supply better results than the previous researches, which are only based on one function model, especially in the preservence the edges between different surfaces. The method is evaluated on synthetic and real data delivered by a shape-from-shading algorithm. The approach provides an actually way to use the normal maps of the surface.