In order to improve the laser deposition repair quality of BT20 titanium alloy, an electromagnetic stirring device was introduced to assist laser deposition repair, and the effects of rotating magnetic field on the macromorphologies, microstructures and micro-hardness of the laser repair layer were studied by changing the magnetic field intensity and magnetic stirring speed. The results show that under the effect of the electromagnetic field, the surface is flat. Meanwhile, the lamellar α/β in laser repaired zone is mechanically broken, the length of intra-crystalline α layers is reduced, but the thickness of α lamellar is almost the same, 0.4~0.5 μm, so the grains are refined and the microhardness increases. As the field intensity and the stirring speed increase, the micro-hardness of repaired parts also increases, while the micro-hardness of the repaired zone tends to be homogenization with certain parameters.