A polarization-independent liquid crystal (LC) grating with a microscale LC molecular alignment pattern is proposed. The microscale LC alignment pattern is achieved using a microrubbing technique. The optical properties of the proposed LC grating are theoretically discussed in detail using Jones matrix method. Optimum condition for obtaining maximum +1st or -1st diffraction efficiencies is derived. The diffraction efficiency of the LC grating is measured and the diffraction efficiency characteristics are compared with the theoretical result. Furthermore, the dependence of the polarization direction of the incident light on the diffraction efficiency is discussed.