Cognitive Radio (CR) is considered as an effective technology for alleviating the spectrum shortage problem by enabling secondary users to utilize vacant spectrum allocated to a primary user (PU). IEEE 802.22 which is the first standard based on CR is developed to increase the efficiency of TV bands. However the physical layer security of IEEE 802.22 has been studied rarely. In this paper, we propose a scheme to sense the specific primary user for dealing with Primary User Emulation (PUE) Attack which is a possible threat to wireless security. According to ATSC digital TV which is one of the important PUs, we estimate the accuracies of pilot and symbol rate as RF fingerprint (RFF), and Support Vector Data Description (SVDD) is introduced to sense the fine differences of RFF to distinguish PUE attacker from PU. The simulation results show that the proposed scheme is feasible to verify the PUE attacker at a relative high SNR level.