Guide signs have a very good role in guiding people's travel, and good design of guide signs can improve the efficiency of drivers. The amount of sign information at the nodes in the road network affects the driver's reading of the sign information, which in turn affects the access efficiency of the whole road network. Therefore, by introduced the amount of guidance sign information from nodes as a penalty coefficient, the cost of the road segment was calculated, and a guidance path planning model between origin to destination (OD) was established, Combined with the A^* algorithm, the entire road network was traversed to obtain the optimal guidance path between ODs. By added guidance information on the guidance path, the coherence of guidance sign information between ODs was improved, guiding drivers can make better path, and reduce traffic pressure in the road network. At last, Select the area from the railway station (point O) to the People's Hospital (point D) in Qingyang City, Gansu Province for practical application and analysis.