A novel cyanine dye Ⅰ that contained triphenylamine donor and carboxylic acid acceptor bridged by a low-band-gap benzothiadiazole conjugation fragment was synthesized,and we also synthesized the corresponding cyanine dye without benzothiadiazole (Ⅱ) for the purpose of comparison.Their absorption spectra,electrochemical and photovoltatic properties were studied.Upon adsorption on a TiO2 electrode,the absorption spectra of the two cyanine dyes are all broadened forward to both red and blue sides compared with their respective spectra in acetonitrile and ethanol mixture solution.Cyanine dye (Ⅰ) containing benzothiadiazole group has stronger absorption intensities and broader absorption spectra than that of Ⅱ,which consequently leads to a better light-to-electricity conversion property.Ⅰ generated higher photoelectric conversion yield of 7.62 % (Jsc =22.10 mA cm-2,Voc =0.54 V,FF =0.48) under irradiation with 75 mW cm-2 white light from a Xe lamp.