The surface atomic and electronic structures of cuprous halide CuX (X = Cl, Br, and I) films, which were grown on various GaAs faces, have been studied by reflection high-energy electron diffraction, Auger electron spectroscopy, and electron energy loss spectroscopy. Epitaxial growth in a layer by layer fashion was observed commonly on all GaAs faces, except on a GaAs (1 1 1) As 2 x 2 race. The growth mode at the initial stage was affected by the lattice misfit of CuX to GaAs. Auger electron spectra and electron energy loss spectra of CuX depend on the crystal race of the substrate. These results indicate that CuX have both ionic and covalent Features in the film growth process.