On the basis of analyzing the difference of service function between the suburban highway and municipal road, the basic principle of cross section design stage and the main influencing factors of decision making in the implementation of urbanization reconstruction of suburban highway are discussed. It is clear and definite that the highways after urbanized and reconstructed should be dominated by the municipal use. And at the same time, it is suggested that Grade I and above highways are determined to be the four-carriageway roads and tow-carriageway roads, and Grade II and below highways to be the three-carriageway roads and single-carriageway roads after reconstructed in the stage of cross section design. Finally, each carriageway width is recommended.