Abstract: The properties of AODV is introduced in this paper.Then both small scale and large scale simulation models of Ad hoc are established based on Opnet Modeler 10.5.The performances of AODV in the two kinds of models is compared and analyzed by varying speed of nodes and size of packets in different sceneries, including the route discovery time, the number of hops per route, the throughput, the average end-to-end delay of data packets and the packet delivery fraction.