We investigated electrochemical characteristics of gold electrodes modified with photosensitizer-tethered DNA. We synthesized 3'-thiol-modified DNA strands (ODN-SH) and 3'-anthraquinone-modified DNA strands (AQ-ODN). We prepared an AQ-ODN/ODN-SH duplex-modified electrode through hybridization of AQ-ODN with ODN-SH on the gold electrode. We used an amperometric technique for its photocurrent measurement. The large photocurrent was observed by irradiation of a DNA modified electrode at 365 nm. We also measured photocurrent with different DNA sequences on gold electrodes.