The mechanism of material removal by electrochemomechanical magnetorheological polishing of glassy carbon (GC) products is studied in this paper. Potentiostatic experiment was performed to examine the electrochemical oxidation mechanism and the associated oxide film growth on GC. A nanoindentation test revealed that the oxide film had lower hardness than did the original GC. An electrochemical impedance spectroscopy experiments were carried out to model the electrochemomechanical material removal mechanism. A series of tribocorrosion tests were conducted to quantitatively study the tribocorrosion synergism.