Cognitive Radios (CRs) are the radios that are widely used in the wireless networks. It is a software based air interface network. Due to the air interface, the probability of attacks increases. In cognitive radio network, an attack can be defined as an activity that can cause interference to the primary users or licensed users. Primary User Emulation Attack (PUEA) is a major threat to the spectrum. In this paper, to prevent from the PUE Attack firstly Distance Ratio Test (DRT) is used which is a transmitter verification procedure based on location verification is used which calculates the Received Signal Strength (RSS) of the signal.