A new mesoporous carbon nanofibers modified pyrolytic graphite electrode（MCNF/PGE） was prepared and applied in the electrochemical determination of rutin.The characteristics of MCNF/PGE and the electrochemical behavior of rutin on the modified electorde were investiged by different methods including cyclic voltammetry,electrochemical impedance spectroscopy and differential pulse voltammetry.The results showed that MCNF/PGE had a good electrocatalytic response to the electron transfer of ［Fe（CN）6］3-/4-.The system presents features corresponding to a diffusion-controlled process of rutin on the surface of MCNF/PGE.Compared to the bare PGE,the proposed modified electrode possesses a high electrocatalytic activity towards the redox of rutin because of the large amount of edge plane-like defects,the large surface area and the mesoporous structure of MCNFs.The anodic peak current（Ipa） of rutin at the MCNF/PGE is 18-fold higher than that of the bare PGE.Under the optimal conditions,the anodic currents of rutin are linear with its concentrations（C） in the range of 2.0×10-8-1.2×10-6 mol/L with a detection limit（S/N=3） of 5.0×10-9 mol/L.The linear equation is Ipa（μA）=-0.415 + 39.104 c（μmol/L）,with a correlation coefficient of 0.999.In addition,the electron transfer coefficient（α）,standard rate constant（ks） and the redox mechanism of rutin at the modified electrode were calculated.The MCNF/PGE exhibited distinct advantages of simple preparation,surface renewal,good reproducibility and good stability,and can beused as a good electrochemical sensor for the determination of rutin in real tablet analysis.