Structural Health Monitoring (SHM) has been one of the most particular concerns of the civil engineering community worldwide, especially in North America, EU and some Asia countries such as Japan, China andK orea etc. The essence of SHM can be considered to involve measurement, inspection, and assessment ofi n-service structures on a continuous basis with minimum labor requirement. Therefore, the challenging problems we are facing are effective sensing, reliable data gathering, rational data interpretation, correct decision making and accepted cost. In this paper, the basic concept, the needs, and the composition of SHM and basicfl owchart for implementing a SHM program for infrastructure, and the international activities are illustrated and presented first. Then the current-status on developing the element technologies such as sensing technology, data communication and information technologies and modeling feature selection and diagnosis technologies are briefly reviewed. Furthermore, the future research directions of R&D, and design code and standardization for SHM are also discussed.