In order to solve the problem of spectrum sensing under primary user emulation attack (PUEA), a cooperative spectrum sensing technology based on the attack-aware threshold (ART) is proposed. Firstly, this method first establishes a network model with PUEA. Then the characteristics of the cooperative spectrum sensing under the four states are analyzed, and the first moment and two moments of the detection statistics are used to estimate the probability of PUEA. Finally, the total error probability is taken as the objective function. We get the best threshold and accomplish the cooperative spectrum sensing under different attack intensities through the ART method. Simulation results show that this method can estimate the probability of occurrence of malicious signals, effectively reduce the total error probability of spectrum sensing, and improve the spectrum sensing performance of the whole network.