HAuCl4 was dispersed into multi-walled carbon nanotube to get MWCNT- HAuCl4 complex. A MWCNT - HAuCl4 modified glassy carbon electrode was charged at negative potential to get gold nanoparticle doped carbon nanotube glassy carbon electrode (GNP doped CNT/GCE). The electrochemical behavior of Nonylphenol was investigated by cyclic voltammetry(CV). The oxidation peak current was significantly enhanced by GNP doped CNT/GCE in contrast to bare GCE. Under optimizing the experimental conditions, the oxidation peak current varies linearly with the concentration of Nonylphenol over the range from 3?0-7 to 4?0-5mol/L with the linear correlation coefficient is r=0.9946, and the detection limit is 1.5?0-8mol/L. The spiked recovery of the samples is 92.6%-101%.