In this work, new Cu-coated biochar composites for the adsorption of Re(VII) through complexation mechanism was synthesized successfully. The sensitivity of Cu-coated biochars to solution pH decreased greatly and the adsorption capacity was increased by 3-12 times compared with pristine biochar at pH 3-6. The environmental effect factors and mechanisms of Re(VII) adsorption onto Cu-coated biochar composites (Cu-BC) were investigated. The Re(VII) adsorption nicely fits the Redlich-Peterson isotherm model, and the recovery of Re(VII) from acidic solution by Cu-coated biochar composites follows pseudo-second-order kinetics. Besides, the thermodynamic parameters depicted the spontaneous endothermic nature for the adsorption of low concentration Re (VII). These results demonstrate that easily synthetic Cu-coated biochar composites have promising potential for the recovery of low concentration Re(VII) in acidic solution.