Road traffic is the most widely used for transport security, which have the significant disaster vulnerability. It often becomes the weak link when the evacuation and rescue. MapX is an ActiveX control product with powerful map analysis functions offered by MapInfo Company. Because it does not support the topology of spatial data, the shortest path analysis has become a hot potato for users to develop application systems. In this paper, several key technologies to establish topology structure of road network based on MapX are discussed. On the base, an algorithm for finding the shortest path in post-disaster road network is presented, and experimental results show that the proposed algorithm is more practical and effective. At last, a brief conclusion as well as the expectation for the further study is made.