Angle resolved ultra-violet photoelectron spectroscopy( ARUPS) and high resolution electron energy loss spectroscopy (HREELS) are used to investigate the surface states of GaP (111) surf aces prepared by ion bombardment and annealing. It is found that the intrinsic occupied surface states related to P atom dangling bonds are located at 0.6 eV below the valence band maximum, while the defect induced empty surface states are located at 1.1 eV above the valence band maximum (Γ point). A 1.36 eV band bending in surface region is induced by these empty surface states.