ELID (electrolytic in-process dressing) grinding was proposed by one of the authors for automatic dressing the grinding wheel while performing grinding for a long time. It offers a high effective way and has been widely used for grinding hard and brittle optical materials. However, those surfaces produced by fixed abrasive grinding are characterized by considerable sub-surface damage, micro-crack. Magneto-rheological finishing (MRF) is a novel precision finishing process for deterministic form correction and polishing of optical materials by utilizing magneto-rheological fluid. In this paper, an ultra-precision synergistic finishing process integrated MRF and ELID grinding is proposed for shorten total finishing time and improve finishing quality. A lot of nano-precision experiments have been carried out to grind and finish some optical materials such as silicon, silicon carbide, etc. ELID grinding is employed to obtain high efficiency and high surface quality, and then, MRF is employed to improve further surface roughness and form accuracy. In general, form accuracy of ~ λ/20 nm peak-to-valley (P-V) and surface roughness less than 10 Angstrom are produced in high efficiency.