The time dependence in the surface treatment of TiO2 photoelectrode on the photovoltaic properties of dye-sensitized solar cells (DSSCs) was studided. Nanoporous TiO2 electrodes were modified with aqueous sodium sulfate (Na2SO4) solution (0.05M) by a dip coating process at varied dipping time, and the resulting electrodes were applied to DSSCs. Fill factor values were significantly decreased with increasing dipping time, and short circuit current values were ranged from 18.11 to 21.53mA/cm(2). However, there were no meaningful changes in open circuit voltage. The power conversion efficiency (PCE) of 6.59 similar to 9.35% was obtained from the DSSCs with Na2SO4-modified TiO2 photoelectrode. Even small differences in dipping time, PCEs were significantly changed.