Magnetorheological finishing (MRF) is a novel precision optical machining technology. Owing to its flexible finishing process, MRF can eliminate subsurface damage, smooth rms micro roughness and correct surface figure errors. The finishing process can be easily controlled by a computer. Through proper designing of numerical control, sphere and asphere optics can be machined by magnetorheological finishing with high quality. Optical sphere is machined using dwell time algorithm and surface shape 2 pt. PV has been improved from 0.17um to 0.07um.