In this paper, a blackboard-based road image understanding system is implemented. The 7 useful information which organized by the hierarchical manner are stored in the blackboard system. The 6 Knowledge source modules and the blackboard make the communications under the supervision of the control module. For a scene, each hypothesis is generated and then verified for every meaningful object. On the simulation results, the correct recognition ratio can be reached out 90%. It shows that the extraction of road information for the autonomous navigation can be obtained using the blackboard architecture.