A method for managing a channel set for dynamic channel allocation, and a system for performing the method. The method includes predicting a channel state and a channel quality on a vacant channel based on channel information that is obtained by spectrum sensing and communication protocol. The predicting includes modeling an occupation pattern of the vacant channel to calculate a probability in which an incumbent user (IU) licensed to use the vacant channel appears on the vacant channel. The method also includes evaluating reliability on the prediction result, and giving a priority to the vacant channel based on the evaluated reliability.