Disclosed is a cooperative spectrum sensing system using sub-Nyquist sampling, which include: a plurality of secondary user terminals for detecting a frequency band occupied by a primary user terminal; and a fusion center, wherein each of the secondary user terminals may include: a receiving unit for receiving signals from the primary user terminal; a sampling unit for performing the sub-Nyquist sampling for the received signals at a predetermined down-sampling rate; an energy-detecting unit for detecting the frequency band occupied by the primary user terminal by detecting energy for the sampled signals; and a calculating unit for calculating a correct detection probability and a false alarm probability for the frequency band occupied by the primary user terminal by using spectrum of the frequency band, and for transmitting results of calculation to the fusion center.