Abstract: A sapphire substrate, of which transmittance is higher than 90%, includes two opposite surfaces, wherein at least one of the surfaces has a plurality of bumps thereon, and the surface roughness of the surface with the bumps is less than 100 nm. The distance between tops of two neighboring bumps is between 150 nm and 500 nm. Each of the bumps is higher than 60 nm. For each bump, the ratio of the height and the width of a bottom thereof connected to the corresponding surface is greater than 0.4. The sapphire substrate can be used in products such as all kinds of lens protective covers, panels, and smart phones.