To accomplish the processing to aspherical mirror with large aperture, the tri-station processing center was designed which has three work stations. Based on the processing center, an aspherical processing model was established. With two rotating axes, it could be used to accomplish the full aperture processing. To verify the practicability of the model, with actual project, the processing to a Ф1 450 mm off-axis parabolic mirror was finished. The result shows that after a cycle of processing, the map of the mirror restraint from PV 4.653 μm, RMS 0.409 7 μm to PV 3.585 μm, RMS 0.258 1 μm. The converging rate of RMS is 37%, which verifies the accuracy and practicability of the model.