In the photoelectrode, the important factor to achieve high efficiency of dye-sensitized solar cells (DSSC) is weak acid treatment rather than specific regime of heat treatment. Acetic acid treatment is advantageous for the adsorption to molecules and enhancement of the photoelectric performance of DSSC. It was found that DSSC showed better photovoltaic performance when the TiO2 paste was treated by acids. The acid treatment of TiO2 electrode provides useful information to understand the mechanism of energy conversion of DSSC.