The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite of silver nano-network and graphene oxide (GO) composed flawless film for the transparent bottom electrode of PVSC. Our experimental results show that the amount of GO flakes plays a critical role on forming the flawless anti-corrosive barrier on silver nano-network through self-assembly approach at room ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting property for a practical bottom electrode by controlling reduction degree of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.