The invention discloses a determination device and method for network resource usage. The device includes a management module used for storing and updating transformation situations of use statuses of the network resources of a primary user, wherein the transformation situations comprise each of a plurality of use statuses of the network resources transforming to other use status; and a determination module used for predicting a use status of the network resources of the primary user in current period in accordance with a use status of the network resources of the primary user in a period prior to the current period and other use status transformed from the use status in the period prior to the current period in the transformation situations under the condition of predicting the resources in the current period, and determining network resources which may be used by a secondary user in the current period depending on the predicted use status in the current period. The invention may predict the use statuses of the network resources of the primary user in the current period reasonably, thereby decreasing the time of sensing and overcoming the hysteresis of the secondary user for using the resources.