The electrochemical properties of catechin at single-walled carbon nanotubes (SWNTs)-cetylramethylammonium bromide (CTAB) modified glassy carbon electrodes (GCE) were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The SWNTs-CTAB film was characterized with transmission electron microscopy (TEM). A series of parameters including pH of supporting electrolyte, accumulation potential and accumulation time were optimized. There were three peaks of catechin at SWNTs-CTAB/GCE in the potential range of -0.4-1.0 V in PBS (pH 7.0): a reversible pair of peaks and an irreversible peak of the anodic peak. The reductive peak current increased linearly with the concentration of catechin in the range from 3.72 x 10(-10) to 2.38 x 10(-9) M. The detection limit was 1.12 x 10(-10) M. The SWNTs-CTAB/GCE showed good stability and low detection limit, and could be applied to detect trace catechin.