Internet of Things (IoT) is a heterogeneous, mixed and uncertain ubiquitous network, the application prospect of which is extensive in the field of modern intelligent service. Having done a deep investigation on the discrepancies between service offering and application requirement, we believed that current IoT lacks enough intelligence and cannot achieve the expected increasing applications’ performance. By integrating intelligentthought into IoT, we presented a new concept of Cognitive Internet of Things (CIoT) in this paper. CIoT can apperceive current network conditions, analyze the perceived knowledge, make intelligent decisions, and perform adaptive actions, which aim to maximize network performance. We modeled the CIoT network topology and designed cognition-process-related technologies, analyzed the payoffs of cooperative cognition based on game theory, which illustrates those novel designs can endows IoT with intelligence and fully improve system’s performance. Finally, an application example was introduced based on the concept of CIoT.