We fabricate solar cells based on blends of poly(3-hexylthiophene) (P3HT) as the donor and [6, 6]-phenyl-C60-butyric acid methyl ester (PCBM) as the acceptor using various solvents such as pure chlorobenzene (CB), pure chloroform (CF) and mixed solvent (CB/CF) with different ratios.We investigate the influences of various solvents and mixed solvents with different ratios on the performances of solar cells. The results show that for the device by using a mixed solvent of CB/CF (3/1), its UV-Vis absorption spectrum and external quantum efficiency show a red-shift and its AFM image shows finely structured phase segregation between P3HT and PCBM. We obtain an open circuit voltage of 0.61 V, short circuit current density of 9 mA/cm2, fill factor of 57.9%, and power conversion efficiency of 3.2% under irratiation of light with a strength of 100 mW/cm2.