Abstract: P(St-co-MMA) microspheres surface-coated magnetic graphene oxide (P(St-co-MMA)/Fe₃O₄/GO) were synthesized by an inverse coprecipitation in-situ compound technology using monodispersed P(St-co-MMA) microspheres as carriers,FeCl₃·6H₂O and FeSO₄·7H₂O as precursors,NaOH as precipitant in the presence of GO.The morphology,crystal structure,chemical structure,Brunauer-Emmett-Teller(BET) specific surface area and magnetic properties of the P(St-co-MMA)/Fe₃O₄/GO composites were characterized by Scanning Electron Microscopy (SEM),Transmission Electron Microscopy (TEM),X-ray powder diffractometer (XRD),Fourier Transform Infrared spectroscopy (FT-IR),nitrogen adsorption-desorption isotherms and Vibrating Sample Magnetometer (VSM).Results showed that the nano-size magnetic graphene oxide was successfully coated on the surface of the micro-sized P(St-co-MMA) copolymers.The average pore width,the volume of pores and the BET specific surface area of P(St-co-MMA)/Fe₃O₄/GO were 14.55 nm,0.204 2 cm³/g and 56.14 m²/g,respectively.The P(St-co-MMA)/Fe₃O₄/GO micro-nano composites were superparamagnetic and had good magnetic responsibility,which could meet the demand of magnetic separation.