W ith the wide application of wireless communication, Mobile Internet business nee ds rapid growth, and the static spectrum planning policy makes available spectru m resources become more and more scarce. Cognitive radio can change the working parameters in real time by sensing the spectrum environment, so as to realize the dy namic spectrum allocation. It provides theoretical and technical support to solv e the problem of spectrum scarcity，and has drawn significant attention in wirel ess communication fields. First， the research status of cognitive radio system and standard are introduced, then three key technologies of s pectrum sensing, spectrum sharing and power control are in depth analyzed, and f inally the application prospect of cognitive radio is summarized, including the t hree aspects of TV white space, energy harvesting and 5G network, and th e research on wireless resource management, seamless handoff and load balance is discussed ba sed on cognitive radio technology in the heterogeneous ubiquitous network enviro nment in the future.