Abstract: A magnetic field regulating ion source introduces strong pulsed magnetic field in the discharge plasma region of the ion source. On one hand, it forms Penning discharge effect to enhance the collision ionization efficiency of the atoms and gas molecules due to the magnetic field. On the other hand, the light ions are restrained along the axis by the strong magnetic field, but it can’t restrain the heavy metal ions. This phenomenon results in the heavy ions loss by colliding wall of the plasma expansion extraction channel, so it promotes the ratio of the light ions. Discharge structure of a magnetic field regulating ion source and strong pulsed solenoid magnetic field, as well as the optic structure of extraction beam are designed and depicted in this paper. Intensity of extraction ion beam and beam spot on the target measured by scintillator screen are analyzed in this paper. The results show that the strong axial magnetic field increases the proportion of light ion components as the result of filtering effect for plasma with mixed ion component.