Abstract: This study focuses on a novel energy detection algorithm for spectrum sensing in cognitive radio networks. How to set the decision threshold is the key part of the energy detection and our novel energy detection gives out a new method to set the threshold via the experiment results. In the conventional energy detection, the threshold is set by the energy that changes with the SNR, however, the ratio of the maximum energy to the mean energy of the received signal, which is dimensionless and nearly a constant, is used to set it in this study. At the same time, the fourth-order moments are used in the novel energy detection algorithm. The performance of this novel algorithm is investigated by Monte-Carlo simulation and compared with that of the conventional energy detection and enhanced energy detection algorithms. The simulation results show that the performance of the proposed algorithm is enhanced by at least 3 dB, when Pd is lager than 0.8, comparing with the enhanced energy detection in Hao’s study.