The magnetic nano-scale biosorbent (Fe3O4/MFX) was synthesized by the chelation and cross-linking procedure with extracellular polymeric substances (MFX) and Fe3O4. Fe3O4/MFX possessed the porous structure and numerous functional groups (i.e., amino, carboxyl, and hydroxyl), and its core region had a typical size of similar to 11 nm. The maximum adsorption capacity was 56.04 mg g(-1) at pH 6.0, 10 mg L-1 of tetracycline, and 160 mg L-1 of Fe3O4/MFX. The data is properly fitted by the Langmuir, Freundlich, and pseudo-second-order kinetics models. As elucidated by the model parameters and FTIR analysis, chemical ion exchange and -COOH could mainly contribute to the adsorption. Meanwhile, the desorption and regeneration experiments implied the adsorption efficiency decreased by only 3.37-8.37% after five adsorption-desorption cycles, and the detection of iron leaching by ICP-OES showed a fine stability of Fe3O4/MFX. Therefore, this technically facile, easily recyclable, and environmentally friendly biosorbent has potential for practical applications in antibiotic removal.