Abstract: In view of the poor performance of conventional wideband energy detection methods for detecting low signal to noise ratio (SNR) line spectrum targets, a linear spectrum target detection method based on target DOA distribution information entropy weighting is proposed in this paper. The detection performance of this method is analyzed through simulation and its effectiveness is verified by the offshore experimental data. The results show that, when the target orientation is relatively stable, this method can effectively detect line spectrum targets with low SNR, and can be applied in the case of multiple line spectrum targets at the same frequency.