In this work, the effects of blocking layer and optimally fabricated electrolyte were investigated with respect to impedance and conversion efficiency of the cells.A layer of $TiO_2$ less than ~200nm in thickness, as a blocking layer, was deposited by rf sputtering onto the F:$SnO_2$ (FTO) glass to be isolated from the electrolyte in dye-sensitized solar cells (DSCs). Also, optimum condition of electrolytes preparation for DSCs was investigated. 3-methoxyppropionitrie and redox pairs with LiI and $I_2$ were used as solvents for fabrication of electrolyte. The electrochemical impedances of DSCs using this photo-anode were $R_1$: 13.8, $R_2$: 15.1, $R_3$: 11.9 and $R_h$: $8.3{Omega}$, respectively. The $R_2$ impedance related by electron transportation from porous $TiO_2$ to FTO showed lower than that of normal DSCs. The photo-conversion efficiency of prepared DSCs was 6.4% and approximately 1.3% higher than general one.