1.The threedimensional currency demonstrator with magnetic induction is mainly used in physical magnetic field teaching in middle school and visually represents the direction of the magnetic field at different points in the space around the magnetic field, as well as the formation of the direction and direction of the magnetic flux. Magnetic field on the induction wire. 2.The instrument consists of a band magnet, a latch magnet, six rectangular transparent magnetic induction plates, a crescent transparent magnetic induction plate and a fixed holder. 3.Shake the demonstrator several times during the demonstration to make the small pieces of iron appear irregular. Pull out the movable plate in a semicircle, insert the crossshaped magnet, stick it to the surface of the plate and tap it lightly. Magnetic core currency appears in a magnetic field. 4.Demonstration experiment to explain the existence of a magnetic field and the spatial distribution of magnetic field lines.