In recent years, the IoT(Internet of Things)has been widespreadly concerned as a new technology architecture integrated by many information technologies. However, IoT is a complex system .If there is no intensive study from the system point of view , it will be very hard to understand the key technologies of IoT. In order to better study IoT and its technologies this paper proposes an extent six-layer architecture of IoT based on network hierarchical structure firstly. Then it discusses the key technologies involved in every layer of IoT ,such as RFID , WSN, Internet ,SOA, cloud computing and Web Service etc. According to this , an automatic recognition system is designed via integrating both RFID and WSN and a strategy is also brought forward to via integrating both RFID and Web Sevice. This result offers the feasibility of technology integration of IoT .