The historic towns in Yuan River basin, with the same origin in water and mountain, has similar geographical environment, interlinked regional economy and inclusive multi-ethnic culture, all of which have a large contribution to both similarities and differences of the space forming of the historic towns. The space form respects for nature with the flexible layout and embodies the leading role of the water transport economy for space form of ancient town. The towns have Similarity of space form elements, convergence of space combinations, ecological of spatial layout and other features. At the same time, diverse types of spatial forms showed peoples wisdom and courage of adapting to nature and working out measures to suit local conditions in Yuan River basin. All these previous experiences supply valuable experience for construction of the small historic town in the present.