The effects of laser power on droplets and weld sizes under different transfer modes are investigated by using the experiment of laser-MAG (metal active gas arc welding) hybrid welding of SUS301L stainless steels. The results indicate that, with the increase of laser power, the metal vapor recoil force increases, the resultant electromagnetic force direction changes, and the droplet transfer is affected. In the short-circuiting mode, the droplets transfer difficultly and are deviated from the wire to laser spot when laser power exceeds 2000 W. In the globule and spray transfer modes, there exist an unstable phenomena in the droplet transfer and welding voltage when laser power is beyond 3000 W. In different transfer modes, the weld penetration and width increase with laser power. After the laser power approaches 2000 W, the weld penetration changes linearly with laser power, while the weld width remains constant.