Abstract: The channel gain consistency of a single vector hydrophone has great influence on the spectrum estimation results. In this paper, theoretical derivation and simulation analysis show that when the gain of the sound pressure channel is not consistent with two vibration velocity channels, the peak of space spectrum estimated by the minimum variance distortionless response (MVDR) algorithm becomes wider, and sometimes false peak appears, which seriously affects the performance of target azimuth estimation. When the gain of a vibration velocity channel is inconsistent with other two channels, the space spectrum estimated by the MVDR algorithm deviated from the true spectrum, and there may be false peaks to further reduce the azimuth resolution of the target. According to the analysis results, combined with the influence of channel gain consistency on the multiple signal classification (MUSIC) algorithm, an analysis method is proposed in this paper to judge whether the channel gain of single vector hydrophone is consistent or not.