Abstract: To ensure the driver to quickly determine export position ,urban expressway exit numbering is gradually used in many cities .However ,many problems still exist including non-uniqueness and disunity in exit numbering and its style in that there is no standard rule at state level .This paper ,on the basis of investigation and research ,proposes an exit numbering setting method that can reflect the features of road ,the flow characteristics to ensure the uniqueness of the exit numbers by illustrating the example of Wuxi Inner-ring West Expressway .Finally ,through contrast test ,the change of driver recognition time between before and after setting exit numbering is compared .It is found out that the legibility of 50% of the examinees is promoted in some degree ,which proves the feasibility and effectiveness of the method .