The invention belongs to the radio communication field, and relates to a throughput-maximized cognitive radio system which aims at enabling secondary users to maximize the radio frequency spectrum not made full use by major users and simultaneously effectively controlling the interference on the major users by the secondary users. The invention uses the collision probability as the measure gauge and control target of the interference on the major users by the secondary users. The system comprises a radio transceiver, a detector, a dispatcher, a transmission controller and a data terminal. By optimally dispatching the secondary-user transmission probability on each transmission sub-time slot in each frequency spectrum idle area, the system maximizes the secondary-user throughput on a single channel and simultaneously limits the collision probability of the major-user data packets within the range of a preset threshold. The system acquires the major-user channel occupying characteristic in a prediction mode, and simultaneously, the performance of the system can be optimized for any secondary-user time slot length.