This Letter reports a series of experiments on examining the removal function of a 400 mm magnetorheological finishing (MRF) polishing wheel which is aimed at large optical component fabrication. This MRF equipment is assembled on the large computer numerical control center whose effective axial length is 3000 mm. The two different removal functions of the wheel are used to virtually fabricate a 1450 mm concave fused silica aspherical optical mirror. The total fabrication times are 110 and 309 h, respectively. The final surface errors are eventually reduced to 0.014λ and 0.024λ after the process, and the convergence rates are 97.46% and 95.65% in one virtual fabrication cycle. The power spectrum density is used to analyze the spacial frequency based on the final simulating surface error, and the middle and low spacial frequency surface error controlling ability is analyzed in terms of different removal functions.