The formation of fighters, UAVs and ships can build a network of moving multi-platforms. High precise space-time synchronization among platforms would play an important role in formation flight, cooperative engagement and detection, but the time delay due to obtaining, transferring and processing space-time reference information has difficulty in space-time synchronization of multi-platforms. Based on the analysis of the applications of the space-time synchronization in dynamic network and their function requirements, a system architecture is proposed, the combination of absolute space-time reference information and relative space-time reference information is processed for space-time synchronization. Technology approaches to relative navigation is presented for relative positioning and time synchronization between platforms.