Taking the urban trunk road in south section of Huaguan Road in Guiyang City as an example, starting from the role, function and positioning of the project, the route direction and main control points are analyzed and expounded to determine the overall layout scheme of the road. The thinking and principle in the overall design of urban trunk road are introduced. The line alignment of the road is determined through the comparison and selection of multiple schemes of the main control nodes. The setting indicators of the road vertical sections and the lane scale of road are demonstrated through the analysis of the control factors of the road vertical and horizontal sections.