Abstract: The β-MnO₂/Mn_xZn_1-xFe₂O₄ composite magnetic catalyst was synthesized via chemical co-precipitation method, and the structure and performance of the composite were characterized by XRD, SEM, FTIR and superconducting quantum interference device (SQUID). The catalytic activity of β-MnO₂/Mn_xZn_1-xFe₂O₄ was studied by using Rhodamine B (RhB) as a simulated pollutant, and its stability was also studied. The results show that the spherical β-MnO₂ and magnetic substrates Mn_xZn_1-xFe₂O₄ are successfully combined together. The β-MnO₂/Mn_xZn_1-xFe₂O₄ composite magnetic catalyst has good catalytic and magnetic properties. When the mass ratio of Mn_xZn_1-xFe₂O₄ and β-MnO₂ is 20:100, in the presence of 2 mL of H₂O₂ (30%), the degradation rate of RhB at a concentration of 10 mg/L (100 mL) in β-MnO₂/Mn_xZn_1-xFe₂O₄ composite magnetic catalyst (93.9%) is higher than that in pure β-MnO₂ (33.7%) within 1 h. Under the magnetic field, the recovery rate of the β-MnO₂/Mn_xZn_1-xFe₂O₄ composite magnetic catalyst is 89%, and the degradation rate of RhB is 76% after five cycles.