The invention provides a device for preparing macromolecular magnetic microspheres. An output end of a pulse laser is connected with an input end of an attenuator; a reflector and a convex lens are arranged between an output end of the attenuator and a bearing part; in the transmitting direction of a reflecting light beam, the bearing part is opposite to a receiving part; a magnetic material layer and a macromolecular polymer layer are successively arranged on the surface, which is opposite to the receiving part, of the bearing part; a focusing point is positioned between the magnetic material layer and the receiving part; the receiving part is arranged on a clamp; the bearing part, the receiving part and the clamp are arranged in a water tank with water; the water tank is arranged on a movable platform; and the pulse laser and the movable platform are connected with a computer. Pulse laser is used as an energy source, a magnetic material reacts with a macromolecular polymer, so that the macromolecular magnetic microspheres are obtained.