Spectrum shortage is a key problem as wireless communication is developing at an increasing rate. Licensed spectrum band users only use a portion of their reserved resources; thus, cognitive radios (CRs) are a necessary component to unlock the unclaimed spectrum through dynamic spectrum management. The goal of Spectrum Sensing is to analyze a specific frequency band regularly, to detect the presence or absence of the Primary User. Cyclo-stationary spectrum density detection technique is robust in the sense that it can detect active or licensed user signals blindly. Cyclo-stationary based detection uses the cyclic autocorrelation function to sense unoccupied spectrum gaps. Signal detection with a low signal-to-noise ratio (SNR) is optimal for cyclo-stationary spectrum detectors. In this paper cyclo-stationary spectrum detection using GNU radio is performed and compared with energy detection method of spectrum sensing.