Superoxide anion,one of the most active reactive oxygen species,is associated with the development of many diseases.So monitoring superoxide anion in living cells is of great significance for the pathological research of many diseases.In this work,a new non-enzymatic sensor for the detection of superoxide anion(O2·-) was developed,which was fabricated by the nanocomposites composed of manganese(Ⅲ) tetraphenyl porphine(MnTPP) as superoxide dismutase mimic and electrochemical reduced graphene oxide(ERGO) as electrode support material to modify the glassy carbon electrode(GCE).The electrochemical behavior of the fabricated electrode(MnTPP/ERGO/GCE) was performed by electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV),which revealed that MnTPP/ERGO/GCE possessed good catalytic ability to the electrochemical reduction of O2·-.The MnTPP/ERGO/GCE showed excellent electroanalysis performance towards O2·-using the technique of differential pulse voltammetry(DPV) with a linear relationship in the range of 0.2-110.0 μmol/L,a sensitivity of 445 μA·L·mmol-1·cm-2 and a detection limit of 0.039 μmol/L(S/N=3).The real-time monitoring of O2·-from MCF-7 breast cancer cells stimulated by zymosan was realized in this work,which indicates that the MnTPP/ERGO/GCE hold potential application for electrochemical quantification of superoxide anions in biological applications.