Based on spectrum sensing, dynamic spectrum allocation and reconfiguration technologies in Cognitive Radio (CR ), this paper fully considers the matching issues between short-term spectrum characteristic and service characteristic. In the communication process, the network-side selects switch terminals to initiate handover command to solve problems due to limited capacity of the system, such as overload and new session decline, improving the success rate of switching on the premise of ensuring user’s QoS, reducing blocking probability with more session admission, eliminating overload, increasing system throughput, and improving the whole system performance.