The electrochemical behavior of viologen self-assembly monolayer has been investigated with QCM, which has been known as nano-gram order mass detector The self-assembly process of viologen was monitored using resonant frequency (DeltaF) and resonant resistance (R). The QCM measurements indicated a mass adsorption for viologen assembling on the gold surface with a frequency change about 135 Hz and calculated its surface coverage (Gamma) to be 3.5273 x 10(-9) mol/cm(2). Also a reversible redox process was observed and analyzed with an ionic interaction at the viologen/solution interface using DeltaF.