Effect of FTO substrate thickness and TiO ~ thin film thicknes s on efficiencies in dye - sensitized solar cell has been investigated. The conversion effic iency of 3.4 % for lmm- thick substrate is improved to 4.3% when 2mm - thick substrate is used And the conversion efficiency of 4.3% for lOt/l11 - thick TiO~ layer is improved to 4.9% when 21μn-thick iO ~ ILl yer is cOLl ted. lmprovement of effici ency on ubSlr Ll le and TiO~ layer thickness L1 re L1 SS0ci Ll te with the qULlnt ily :J nd \v:J vc :cnglh 01 transmitted ligh t.