The invention discloses a 1553B bus network emulation system applied to a spacecraft system, which belongs to the field of aerospace and computer emulation. The 1553B bus network emulation system comprises a 1553B bus, the Ethernet, a bus network tester, a bus terminal tester, a digital phosphor oscilloscope, a bus separation switch, an emulation terminal, a bus system performance estimation computer and a bus interface control file configuration computer, and is used for emulating and analyzing the information transmission and system running of an actual spacecraft bus system. The 1553B bus network emulation system replaces conventional cable connection with a 1553B bus network, realizes the digitalized transmission and comprehensive utilization of network system information and improves the reliability and electromagnetic compatibility of the system by equipment with standard digital interfaces in combination with Ethernet communication, meets 1553B specifications, realizes coexistence in one network emulation system, can be used for a plurality of stages of analysis, development, test and the like of the spacecraft system and is of great importance to researches on the reliability of the actual spacecraft system.