This paper first introduced the related protocol of MANET and mobile IP technology, and then presented the research and implementation of AODV protocol of the dynamic gateway based on the MANET and Internet interconnection, including AODV dynamic gateway, system architecture of dynamic gateway, reform of the AODV protocol, gateway switch and load balance. Finally, it introduced the test environment of the system, and verified through NS2 simulation that the load of the network could be reduced by the improved AODV protocol.