Abstract: The development of computer and network technology makes the communication of monitoring instruments with internet possible.From the beginning of several decades ago, after reconstruction and perfecting, instruments of seismic precursor have realized digitalization, and become a web based and intelligentized system.The working mode and data flowing of instrument for seismic precursor, which is an independent node of network, are discussed here.These kind instruments, as centers to supply many service, allow users accessing with several ways, so they facilitate the monitoring greatly.The application of network technology in instruments of seismic precursor made conditions for the real time transmission of precursor data.