A new planarization grinding method based on the cluster magnetorheological (MR) effect is presented to grind optical glass in this paper. Some process experiments were conducted to reveal the influence of the speed of the grinding disc and grinding time and grinding pressure during the machining process. The results indicate that the speed of the grinding disc influences definitively on grinding effect of this planarization grinding method based on the cluster MR-effect. When the speed of the grinding disc is 110r/min, better machining effect can be achieved. Furthermore, the influence of the grinding time on machining effect is obviously, and the proper machining time is 6mins. However, under the experiment condition in this paper, the influence of grinding pressure on machining effect is unobvious.