Light alloys have irreplaceable advantages such as high specific strength and low density. They are indispensable structural materials in aerospace, military, and marine engineering. It is an enduring research hotspot to prepare high-strength and high-toughness light alloys to play a more significant role in advanced engineering applications. As a new method to improve the mechanical properties of light alloys, the magnetic field-assisted process can produce magnetoplastic effects. Therefore, in this paper, research progress on the magnetoplastic effects of light alloys assisted by magnetic fields was reviewed, and the effects of magnetic fields on dislocations, grain refinement, precipitation kinetics, phase transformation, and mechanical properties of light alloys were elucidated. Magnetic field treatment transforms radical pairs from the ground state to the excited state, which reduces the resistance between dislocations and obstacles, facilitating dislocation depinning. Moreover, magnetic field can promote grain refinement and phase transformation, increase precipitation kinetics, and synergistically improve strength and elongation. Finally, the prospects of magnetic field-assisted processes of light alloys were discussed.