Metallic film as an indium tin oxide alternative, which shows excellent mechanical flexibility and high conductivity, has the ideal physical properties for flexible organic solar cells (OSCs). However, a bottleneck of metallic film was a lack of transmittance that limits the application in OSCs. We have demonstrated a nanoaperture metallic film fabricated by a template striping method, which can overcome the above-mentioned bottleneck. This metallic film has a random nanoaperture array. The size and shape of the nanoaperture were dependent on master templates. This metallic film with nanoaperture array is not only able to show high conductivity but also possesses tunable localized surface plasmon (LSP) resonance as well. The LSP could be coupled with dipole mode in nanostructure, which can account for the transmission enhancement and efficiently increase the light absorption of active layer in the OSCs. Moreover, this metallic film with nanoaperture array will exhibit particular advantage in flexible OSCs because the backing layer itself is a flexible substrate. The nanoaperture metallic film fabricated by this method as an electrode was a good choice for OSCs.