Alternative energy sources such as solar energy have attracted an extensive interest in the petroleum shortage era. Among solar cells, dye-sensitized solar cell (DSSC) attracts the attention of widespread research teams because of the easy-production process, low cost, and good photon-to-electron conversion efficiency. In this study, both UV and acid solution such as HCl are used to improve the efficiency of DSSC. The UV illumination can eliminate organic contaminates on TiO2 by photocatalysis and enhance the adsorption of dye molecules. Meanwhile, the coordination mode between TiO2 and dye could be changed and lower the electron transportation. If the HCl solution is used after UV illumination, the coordination mode can be preserved. Moreover, H+ from HCl can attract the COO¡Ð anchoring group of dye by electrostatic force. It further increases the adsorption of dye and improves the DSSC efficiency. The coordination mode was measured by Fourier-transform infrared spectrometer (FTIR). The internal resistance was measured by electrical impedance spectroscopy (EIS). The chemical properties were characterized by X-ray photoelectron spectroscopy (XPS). The light absorbance was measured by ultraviolet-visible spectroscopy (UV-Vis). The morphology was observed by field emission scanning electron microscope (FE-SEM). The performance of the cells was measured by a semiconductor device analyzer. In our results, the conversion efficiency was improved from 6.29% of untreated one to 6.71 and 7.39% for UV and UV + HCl treated ones.