Abstract: Traditional flocculants cannot be used to effectively remove the soluble dyes. In this study, graphene oxide (GO) was synthesized by means of modified Hummers and evaluated for its material characteristics and efficiency for flocculating water-soluble cationic dye methylene blue (MB) from wastewater. The effects of pH, coagulant dosage, initial MB concentration and stirring time on MB removal were investigated. Flocculation mechanism was also explored in combination with zeta potential measurements and FT-IR. Moreover, several common inorganic and organic flocculants were compared with GO in their efficiency for MB removal. The results indicate that GO exhibits much higher efficiency in flocculating MB than the usually used flocculants. High removal efficiency (95%) is achieved by GO at the optimum conditions of the MB initial concentration of 70 mg/L and 180 mg/L GO with 9 min stirring time at pH 4. The predominant flocculation mechanism of coagulant GO is the coexistence of the neutralization mechanism and the adsorption bridge mechanism. The results of this research suggest that GO may be used extensively in the future in flocculating soluble cationic dyes for its high efficiency and extensive pH application.