Abstract: Aiming at the problem that existing spectrum detection algorithms can not deal with the difference of noise base between different channels, a channel detection algorithm based on morphological operation is proposed. Firstly, morphological operations are used to estimate the base of the channel noise, and the effect of the complex noise background is eliminated. Energy detection algorithm is then used to determine the detection threshold, and the sub-band signal detection is realized. The simulation results show that the proposed algorithm can complete the channel detection and decision in the background of noise fluctuation, and the detection probability is better than that of the traditional energy detection algorithm.