The pressure effect on the polarization of electronic excited state in a GaN/GaAlN quantum well is studied. The effects of the anisotropy of the wurtzite structure on the strain and the hydrostatic deformation potential are considered, including the build-in internal electric field. It is shown that, all of the electronic barrier height, the electronic effective masses and the strength of the polarization of the electronic excited state decrease linearly with pressure. But because of the localization of the electronic wave functions caused by the build-in internal electric field, the decreases are small.