Abstract: Road characteristics are not fully used in road extraction methods based on pixels.In this paper,an object-oriented road extraction method based on road-unit is proposed.First,a road-unit is defined according to the road characteristics.Then,searching,construction,tracking and connection of road-unit were completed with region growing support.The preliminary road network was extracted and a method to repair the road information was designed to obtain the final road network.GeoEye satellite image experimental results validated that the proposed method is practical and effective.