In this study, by measuring the white light interference images, scanning electron microscope pictures and whiteness, transmittance, fine whiteness, L value, a value and b value of japonica rice with different bran degrees, the changed of japonica rice appearance and characteristics were studied. Studies showned that the grain cortex on both sides of the rice grain is ground first, and the abdomen and back of the rice grain are difficult to grind; the surface roughness increases first and then decreases with the bron degree; Aleurone layer and endosperm cell structure, as the decreases of bran degrees, are milled layer by layer; the whiteness, permeability, fine whiteness and L value of the sample are gradually increased, and the a value and b value are gradually reduced.