Structural Health Monitoring (SHM) system uses a number of sensors for a precise prediction. This prediction enables to provide early indication of vulnerability of a structure and the timing of reinforcement in order to prevent future collapse. SHM systems are now widely spreading in infrastructures. However, conventional SHM systems did not take account of accidental collapse. There is a possibility that sensor node goes down or network goes offline. If sensor nodes are broken by damage, important data, stored in the nodes will have lost. To prevent the data loss, this paper proposes data-distributed fault-tolerant sensor network system for a SHM system. Proposed system consists of three functions, PING (Packet InterNet Groper) based network monitoring function (PNM), backup node selecting function (BNS) and socket communication function. Proposed system is implemented on PCs and practically evaluated in a laboratory environment on terminals of KNIVES, which is a test bed of sensor network system. As a result, Data sharing process on PC and KNIVES was confirmed and proposed method can provide a light-weight fault-tolerant system taking account of accidental collapse.