Aspherical optical components and systems are greatly demanded by today's optical industry. However, the manufacturing and metrology of aspheric optics remains a difficult task for opticians. For high precision aspheric mirror's quick fabrication, computer controlled magnetorheological finishing (MRF) has proven to be a reasonable approach. In MRF, magnetically stiffened magnetorheological (MR) abrasive fluid flows through a preset converging gap that is formed by a workpiece surface and a moving rigid wall, to create precise material removal and polishing. Tsinghua University recently completed a project with MRF technology, in which a 66 mm diameter, f/5 parabolic mirror is polished to the shape accuracy of lambda/30 rms (working wavelength lambda = 0.6328 mum) and the surface roughness of 0.6739 nm Ra. In this paper, working processes are designed and experiments are carried out on the features of MRF. The results show that the required convergent speed, surface roughness and figure precision could be achieved with high efficiency.