The supergain beamforming is introduced into pressure-gradient vector hydrophone array beamforming here. An acoustic vector hydrophone can simultaneously measure the scalar information - acoustic pressure and vector information of acoustic field - particle velocity at the same spot. In order to take full advantage of this vector information collected by acoustic vector hydrophone, the idea of the supergain energy flux beamforming on pressure-gradient vector hydrophone crossing array is brought forward. Comparing with conventional beamforming, a narrower beam-width and lower sidelobe can be obtained by using this method. And it can be used to preform multi-beam, so it has attractive practical value. The lake experiment result validated this idea in practice