A sewage treatment device provided with a magnetically strengthened MBR (membrane bioreactor) comprises a cylindrical casing provided with an upward opening, static magnets, magnetic coil props, magnetic coils, a cylindrical MBR membrane assembly, a scavenging conduit, an aeration pump and a suction pump, wherein an accommodating cavity is formed in the cylindrical casing; the static magnets, themagnetic coil props, the magnetic coils, the cylindrical MBR membrane assembly and the scavenging conduit are arranged in the accommodating cavity; a ring-shaped clamp groove which is concave downwards is formed in the bottom of the accommodating cavity; at least two magnetic coil props are arranged and uniformly distributed on the ring-shaped clamp groove; the magnetic coils are clamped in bayonets of the magnetic coil props. The sewage treatment device has the advantages as follows: 1, by means of the magnetization effect of a magnetic field, a water molecule structure is changed, water molecular viscosity of sewage is reduced, water molecule activity is improved, difficulty of water molecules passing the MBR membrane is reduced, and membrane pollution is reduced; 2, with the adoption ofthe static magnets and the magnetic coils which can be increased or decreased, strength and direction of magnetic action on the sewage in the device are adjusted, and meanwhile, the magnetic coils can be taken as magnetic conductive rings, so that magnetic force loss is reduced and the magnetic field with uniform magnetic force is manufactured.