We study the Raman scattering of the stretching band from liquid water under pressure up to 6kbar at 290 K.The result shows that the (v1)max intensity decreases with increasing pressure initially and reaches the minimum at about 2kbar, and increases with the further increase of pressure up to about 4kbar, then decreases again with the increasing pressure up to 6kbar. This is in agreement with the behaviour of the average separation roo between the nearest molecules under pressure. Additionally, the influence of pressure on water structure is also discussed.