The Internet of Things (IoT) is aimed at enabling the interconnection and integration of the physical world and the cyber space. It represents the trend of future networking, and leads the third wave of the IT industry revolution. In this article, we first introduce some background and related technologies of IoT and discuss the concepts and objectives of IoT. Then, we present the challenges and key scientific problems involved in IoT development. Moreover, we introduce the current research project supported by the National Basic Research Program of China (973 Program). Finally, we outline future research directions.