Abstract: This paper elaborates the technological system of the National Center of Digital Seismic Network (NCDSN) and its seismic data stream. Computer network system and earthquake hardw are system are the basis of the whole technological system of NCDSN. The main tasks of N CDSN are disaster mitigation and services for the earthquake basic researches. These tasks are implemented by the five technological systems: Seismic data receiving and automatically locating system, man-machine interactive system, half automatic CMT system, seismic data format transformation system, and seismic data management and service system.

Key words: National Center of Digital Seismic Network, Technological system, Seismic data