Vanadium pentoxide V2O5 was inserted between the donor layer and the anode as a hole-extracting nanolayer. Compared with devices without a hole-extracting layer, short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and power conversion efficiency (PCE) of rubrene/C70-based heterojunction solar cells with 3m V2O5 nanolayer are enhanced by 99%, 73%, 20%, and 310%, respectively. We found that V2O5 interlayer can effectively suppress the contact resistance and increase the hole transport capability. The dependence of the device performance on V2O5 layer thickness as well as fill factor on exciton dissociation and charge transport was also investigated in detail.