Chemically reduced graphene oxide (rGO) is widely studied as transparent electrodes, as it can be cheaply prepared on a large scale, easily integrated into flexible devices, and contributes to excellent device performances. However, the commonly used reduction methods to converting graphene oxide (GO) films into rGO ones generally involve toxic reagents or complex transfer steps. In this report, we develop a simple short-term room-temperature strategy for the direct fabrication of rGO-based transparent conductive films on flexible substrates, where tin (Sn) is used to promote the conversion of pre-deposited GO films into rGO ones. The thus-prepared rGO films exhibit sheet resistances of 6.7~17.3k[capital Omega] sq-1 and transparencies of 75~81% at 550 nm, indicating great potential of the here-developed methodology for the fabrication of graphene-based transparent conductive films, at conditions without any heating and transferring processes, as well as toxic agents.