We comprehensively studied the electrical, optical, and mechanical properties, and stability of the hybrid transparent conductive electrode (TCE) prepared by transferring graphene onto random silver nanowires (AgNW) on poly(ethylene terephthalate) (PET) substrates. Compared with the pristine AgNW TCE, the AgNW-graphene hybrid TCE was found to exhibit lower surface roughness, better optical and electrical properties, and excellent long-term stability and flexibility. The power conversion efficiency of the inverted organic solar cells (OSCs) with PTB7:PC71 BM as the active material built on the PET/AgNW-graphene TCE is 6.47%, which is 8% higher than the OSCs built on AgNW TCE, and much better than the OSC with conventional ITO. Moreover, the flexible OSCs built on the PET/AgNW-graphene exhibit excellent properties under curved conditions, which suggest that it is promising for applications to uneven surfaces.