We report a facile and scalable fabrication of flexible conductive graphene thin films via a vacuum filtration method based on high water-soluble sulfonated-triazine non-covalent functionalized graphene colloid (STGNS). A novel sulfonated triazine (ST) molecule was synthesized using a one-step method to improve the dispersion stability of graphene during the chemical reduction. AFM image of STGNS sheets showed the STGNS is individual dispersion of graphene sheets in water. FTIR, and UV-vis revealed ST molecules were successfully loaded onto graphene sheets by hydrogen bonding anchoring and π–π stacking. It was found that the dark homogeneous suspension of the STGNS with concentration up to 4.5 mg mL<sup>-1</sup> can remain stable with no visible precipitate for more than 6 months. The high watersoluble individually dispersed graphene colloid facilitated large-scale fabrication of flexible conductive graphene films with different thickness by adjusting the content of STGNS. The obtained graphene films exhibited a sheet resistance as low as ca. 5.6 KΩ<sup>-1</sup> with 78% transparency at 550 nm.