A new biosensor was fabricated with sol of nanosilver/chitosan（sol-AgCS） and acetylene black（AB） to form a compound film on a glassy carbon（GCE） electrode.The AgCS was characterized by UV spectrometry and scanning electron microscopy（SEM）.The different GCEs were characterized by electrochemical impedance spectroscopy（EIS）.The electrochemical behaviors of ethyl naphthol（β-N） on AgCS-AB/GCE were investigated by cyclic voltammetry（CV）.The results showed that β-N exhibited a sensitive oxidation peak in pH 6.5 PBS buffer solution.The oxidation peak current（Ipa） was linear to v1/2 in the range of 60-240 mV/s,which suggested that the electrode process of β-N was controlled by diffusion.The reaction electronic numbers,diffusion coefficient and other important parameters of β-N were calculated.The different concentrations of β-N were determined by square wave voltammetry,and a good linearity between peak current and concentration of β-N was observed in the range of 3.0×10-7-2.0×10-4 mol/L.The detection limit（S/N= 3） was 1.24×10-7 mol/L and the spiked recoveries were in the range of 99%-105%.