This paper analyses the influences of urban geomorphological environment on the urban road system and holds that the relief volume and dis seeted degree of surface and geomorphological processes change the construction cost of urban roads, and they control the layout of the urban road syste m in a certain extent.Taking several cities in Sichuan province as examples, the author analyses characters of urban road system in mountains, in hills and in plains, and approaches to the effects of various types of urban geomorphological environment in the forming and evolvement of the urban road system.Generally speaking, in mountains and in hills, urban geomorphological environment has a great relief, more dissected surface and more active processes, so it gives clearly effects to the urban road system.In plains, urban geomorphological environment if favourable to the construction of roads, so the urban road system mainly reflects needs of urban traffic, transport and layout.