The purpose of this paper is to identify the critical road sections and intersections in a road network which have great inffuence on the normal transport functions of the road network and to optimize the road network structure by reducing its vulnerability. In this paper,the framework of road network structural vulnerability measurement and improvement model is proposed. The network effciency model is used to define road network structural vulnerability. Shanghai freeway network is analyzed based on this model. We find that using this model the critical components of the road network can be identified. Two methods which are increasing connections and rewiring are proposed to optimize the road network structural vulnerability and the results can be used to reduce the network vulnerability. The measurement method that we put forward for structure vulnerability is useful and important to optimize road network structure. The purpose of this paper is to identify the critical road sections and intersections in a road network which have great inffuence on the normal transport functions of the road network and to optimize the road network structure by reducing its vulnerability. In this paper, the framework of road network structural vulnerability measurement and improvement model is proposed. The network effciency model is used to define road network structural vulnerability. Shanghai freeway network is analyzed based on this model. We find that using this model the critical components of the road network can be identified Two measures which are increasing connections and rewiring are proposed to optimize the road network structural vulnerability and the results can be used to reduce the network vulnerability. The measurement method that we put forward for structure vulnerability is useful and important to optimize road network structure.