In this paper, the technical process and the main points of technology of constructing Tianjin strong motion observation network system by us of VPN technology based on CDMA1X/GPRS network is elaborated. By the construction of this network， Tianjin strong motion observation network has realized the functions of automatic monitoring, automatic data collecting and automatic parameters acquiring, which improve the automatic observation level and management ability of Tianjin strong motion. It would provide us solid technical support for the city′s rapid assessment, emergency and rapid rescue of postearthquake disaster. It would also bring strong motion observation into playing more important role in Tianjin earthquake prevention and disaster reduction too.