Simultaneous determination of o-, m-, and p-dihydroxybenzene isomers were investigated by voltammetry based on the single-wall carbon nanotube (SWNT) electrode. The SWNT electrode exhibited strong and stable recognition ability toward dihydroxybenzene isomers. The oxidation peak potential difference between hydroquinone and catechol was 111mV, catechol and resorcinol 399mV, which indicated that the o-, m- and p-dihydroxybenzene could be identify entirely at the SWNT electrode. The peak currents of dihydroxybenzene isomers increased linearly with increasing the dihydroxybenzene isomer contents. The proposed method can be applied to simultaneous determination of dihydroxybenzene isomers.