Photocurrent polarization properties near the band gap of long-range ordered Ga0.5In0.5P have been investigated. The linearly polarized PC spectra of the ordered Ga0.5In0.5P show an absorption anisotropy for the [110] and [11̄0] directions together with a large band-gap reduction. The anistotropy in the PC spectra is due to a crystal-field splitting at the valence-band maximum in ordered Ga0.5In0.5P. The PC edge of the [110] polarization is lower at about 10 meV than one of the [11̄0]. The polarization spectra defined by (I110−I11̄0)/(I110+I11̄0), where I110 and I11̄0 are the PC signal intensities measured at the [110] and [11̄0], respectively, show a single broad peak. The maximum polarization reaches about 50% at the energy of the transition between Γ6c and Γ4v, Γ5v. With increased sample temperature, the polarization maximum shifts to the lower energy side according to the change of the Γ6c-Γ4v,Γ5v transition energy. Even at room temperature, a clear polarization signal was observed.