The invention provides a polishing process for ultrathin sapphire wafers. The polishing process comprises the following steps of 1, grouping the sapphire wafers obtained after cutting according to thethickness; 2, providing an adsorption pad provided with multiple cavity holes used for containing the sapphire wafers, wetting the cavity holes with clear water, putting the sapphire wafers into thecavity holes, and making each sapphire wafer and the corresponding cavity hole be fixed relative to each other; 3, putting the adsorption pad on a copper disc of a polishing machine with openings of the cavity holes of the adsorption pad facing downwards, so that rough polishing is conducted on the sapphire wafers; and 4, putting the sapphire wafers obtained after rough polishing on a lower polishing disc of a double-face polishing machine for finish polishing. By means of the polishing process for the ultrathin sapphire wafers, the polishing time is greatly shortened, polishing efficiency isimproved, and production cost is lowered; the thickness of each sapphire wafer obtained after polishing is small and can reach 0.1-0.2 mm; polishing quality is stable and reliable; and the polishing process meets the trend that existing sapphire products develop to be lighter and thinner.