A gold nanoparticles/multi-walled carbon nanotubes modified glassy carbon electrode（AuNPs-CNTs/GCE） was prepared,and the electrochemical behavior of 4-n-octylphenol（NP） on the modified electrode was investigated by cyclic voltammetry（CV） and linear sweep voltammetric（LSV） method.In BR buffer solution,a sensitive oxidation peak of NP was found at+0.51 V and the oxidation peak current was significantly enhanced by AuNPs-CNTs/GCE compared with those by bare glassy carbon electrode（GCE） and multi-walled carbon nanotubes modified glassy carbon electrode（CNTs/GCE）.Based on this,a simple and sensitive electroanalytical method was developed for the determination of NP.Factors such as pH,scan rate and accumulation time that influenced the detection processes were optimized.Under the optimal conditions,the oxidation peak current was proportional to NP concentration in wide linear ranges of 0.05-4 μmol/L and 6-14 μmol/L with correlation coefficients of 0.998 4 and 0.993 3,respectively.The low detection limit was 0.023 μmol/L.The spiked recoveries of the samples were in the range of 95%-104%.With the advantages of simple preparation,high sensitivity,low cost,excellent reproducibility and stability,the proposed method could be used in the determination of NP in environmental sample.