The invention discloses a network communication method applicable to a space-based network. A physical layer mechanism applicable to space-based network communication is provided, thus overcoming the defect that the traditional space-based communication is only applicable to point-to-point communication. The method is applicable to the system workflow of multi-point network communication of a space-based system and is in support of a network access process and a service process, therefore the network control and coordination are simple, the signalling cost is low and the network establishing time is short. The expansibility is high, and therefore, network scale and user demand changes are supported. A system frame structure in consistent with the system workflow is provided, and therefore the method is applicable to the network communication demands of current multiple satellites. A physical layer transmission scheme applicable to the multi-point network communication of the space-based system is provided. The scheme comprises a physical layer signal generation process and resource unit structures. Through design of the frame structure, the propagation time delay is ensured, and therefore, the method is applicable to service with high time sequence demand or high timeliness. Various priorities and various service types are supported, and therefore, the flexibility is high. SYN is carried in the frame structure, therefore, according to a synchronization process, the search time is short, the synchronization establishing time is short, and long term tracking is unnecessary.