Further research shows that the reason why the superconducting body can not penetrate the magnetic field in the superconducting magnetic field is that a non-destructive and anti-magnetic superconducting current is generated on the surface of the superconducting conductor. The magnetic field generated by this current happens to cancel The magnetic field inside the superconductor. This finding is very meaningful, after which people use the Meissner effect to determine whether the substance has superconductivity.
In a shallow flat tin plate, place a very small magnetically strong permanent magnet and lower the temperature to make the tin superconducting. At this moment we can see that the small magnet actually left the surface of the tin plate, floating in the air and keeping a certain distance from the tin plate, then it was suspended. This is due to the complete diamagnetic nature of the superconductor, so that the magnetic flux of the small magnet can not penetrate the superconductor, and the magnetic field is distorted to produce an upward buoyancy force.