The present work used mainly electrochemical in situ time-resolved UV-vis subtractive reflectance spectroscopy to study the electron transfer process of cytochrome c in the presence of promoter (the equal molar mixture of guanine and cytosine). Two new absorption bands 450 and 500 nm and two bipolar bands 250 and 300 nm are observed in the spectra with different time resolutions. In addition, the intensity of another band 420 nm changes with the time resolutions. All the results show that the electron transfer of cytochrome c is accompanied by significant conformational rearrangement.