[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) / poly (3-hexylthiophene) (P3HT) heterojunction has not only the absorption in ultraviolet light for PCBM, but also the absorption in visible light for P3HT, which widens the incident light harvest range, improving the photoelectrical response of hybrid solar cell effectively. Using conducting polymers blend heterojunction consisting of C60 derivatives PCBM and P3HT as charge carrier transferring medium to replace I -3 =I - redox electrolyte and dye, a novel flexible solar cell was fabricated in this study. The influence of PCBM/P3HT mass ratio on the photovoltaic performance of the solar cell was also studied. Under a simulated solar irradiation of 100mW$cm-2, the flexible solar cell achieved a light-to-electric energy conversion efficiency of 1.04%, an open circuit voltage of 0.86 V, short circuit current density of 2.6 mA$cm-2 and fill factor (FF) of 0.46.