The m-plane GaN film is grown on LiAlO2 by metal organic chemical vapor deposition. The single crystal orientation of m-plane GaN is demonstrated, According to the X-ray diffraction results, and the anisotropy strain is calculated. X-ray rocking curve at different φ angle shows obvious in plane structural anisotropy. Polarized photoluminescence is employed for the investigation of optical anisotropy. Both the wavelength and the intensity for the emission peak near band edge vary with the rotation of polarization angle, and can be explained by the degeneration of the subbands in valence band under anisotropy strain.