Abstract：Internet of Things (IOT) is the outcome of the development of information technology, and is a new scientific, technological, and economical wave of worldwide information technology enterprises. In the meantime, the information security of the IOT is one of the core technologies that will influence the long-term development of the IOT, and much attention should be paid on it. This paper first analyses the background and significance of the security research in IOT, introduces the national development and level of recognition of IOT, analyses the technical shortages we are facing at, and describes the government support to the IOT technology and industry. Then based on the well-known three-layer architecture of IOT, presents a security architecture of IOT, and by focusing on the sensor layer security and application layer security, this paper analyses some research directions and key techniques that need to be further studied, and indicates the essence and key problems of these techniques. This paper indicates that, in the sensor layer of IOT, lightweight security techniques, including lightweight cryptographic algorithms and lightweight security protocols, are what in practical need and are also the main technical challenges. In the application layer of IOT, privacy protection, mobile device security, IOT security infrastructure, as well as IOT security evaluation systems are the key techniques. With respect to the transmission layer security and processing layer security of IOT, this paper treats them as enhanced network security and cloud computing security respectively, and should not be treated as specific security techniques for IOT, hence they are not addressed in depth in this paper.