In this report, Taguchi experimental design (TED) and response surface methodology (RSM) were used to optimize and model Cr(VI) removal conditions by Fe3O4/Fe-Mn binary oxide/bentonite nanocomposite(FFMB). The effect of variables including Cr(VI) concentration, adsorbent dosage, pH of the solution, and contact time on the adsorption efficiency of Cr(VI) were evaluated by TED. Then, the most important factors were chosen and modeled by RSM to reach the highest efficiency of Cr(VI) removal. The proposed quadratic equation of RSM was consistent with correlation coefficients R2=0,9874 for the actual experimental data. The maximum adsorption capacity of Cr(VI) in the optimal operation condition (solution pH of 2.54, contact time of 314 min and adsorbent dosage of 1,55 g/l) was 64,15 mg/g.