The invention discloses a process method for removing
rainbow lines on the surface of a
monocrystalline silicon optical element, which comprises the following steps of: S1, detecting the
surface shape and smoothness of the
monocrystalline silicon optical element after previous ultraprecise single-point turning, and measuring the
surface roughness of the
monocrystalline silicon optical element; s2, if only the
rainbow lines exist on the surface of the monocrystalline
silicon optical element, the whole surface of the monocrystalline
silicon optical element is swept at a
constant speed through
magneto-rheological
polishing, and the surface of the monocrystalline
silicon optical element is polished and conformal; s3, detecting the smoothness of the surface of the monocrystalline silicon optical element; if the
rainbow lines exist, the step S2 is repeated until the rainbow lines cannot be detected; and S4, detecting the
surface shape of the processed monocrystalline silicon optical element, and measuring the
surface roughness of the monocrystalline silicon optical element. The method has the advantages of being simple in principle, high in
machining precision, high in
automation degree and the like, shape preserving is achieved, rainbow lines are eliminated, the repairing or scrapping problem caused by the appearance problem in previous
machining is reduced, and the method is suitable for
batch production of ultra-precise optical products.