Abstract: With the widespread application of various small aspheric optical components, high-precision manufacturing technology of forming molds is deeply demanded. However, the ultra-precision grinding technology of small aspheric moulds is still undeveloped in domestic research. An ultra-precision single-point grinding technique and profile error compensation mode of aspheric mould are studied. Through processing the measured data generated from contact on-machine measurement, the actual ground profile is reconstructed. Normal residual error is obtained through calculating the normal distance between actual ground profile and target profile, subsequently, a compensation method of profile error based on ultra-precision single-point inclined axis grinding is proposed. An experimental test is conducted to grind an aspheric tungsten carbide mould of aperture 6 mm，and the profile accuracy is gradually improved from peak to valley 449 nm to 182 nm after two-time compensation cycle.

Key words: Aspheric mould, Error compensation, Profile error, Single point grinding, Tungsten carbide grinding