Abstract: In 1931, Paul Dirac, a physicist of Britain, theoretically predicted that magnetic monopoles can exist independently, and believed that since electricity has electrons with basic charges, magnetism should also have magnetic monopoles with basic magnetic charges. Decades later, many scientists failed to find magnetic monopoles although they tried to do that in any way. Some outstanding physicists, such as Fermi, an Italian American physicist, and Yang Zhenning, a Chinese American physicist, believe that magnetic monopoles exist and have improved and supplemented Paul Dirac's theory. In this paper, the author found a new crystal topological material that emits positive and negative magnetic monopole pairs (magnetic dipoles) and magnetic monopoles into space when excited by both alternating magnetic field and heat. A "string" predicted by Dirac exists when the magnetic dipole runs in space and extends and contracts under the action of external magnetic field, and separates into positive and negative magnetic monopoles at given magnetic field strength. Strong “γ” ray is released from annihilation which occurs when positive and negative magnetic monopoles collide with each other. The space speed, magnetic field intensity and magnetic monopole mass under different magnetic fields were measured and calculated. The catalytic fission of magnetic monopoles and the repulsion of antimagnetic materials were characterized. The existence of magnetic monopoles predicted by Dirac was proven by experiments and observations from different perspectives.