Compared with laser welding, laser-arc hybrid welding has a lot of advantages. One of these advantages is to improve the weld metal microstructure and mechanical properties by feeding welding materials. In this case, it is essential to achieve the homogeneous distribution of alloying elements. In deep and narrow hybrid welds, however, it is very difficult to attain the homogeneous distribution. The effect of welding parameters on the distribution of wire feeding elements is investigated during CO2 laser and gas metal arc (GMA) hybrid welding process, and the influence of fluid flow behaviour on the homogeneity of weld metal is also discussed. The results indicate that the homogeneity of weld metal is improved when decreasing the welding speed or increasing the gap width. When the welding direction is leading laser, the molten metal flows from the rear end to the keyhole on the pool surface and then goes down just behind the keyhole during hybrid welding, namely inward flow, resulting in almost homogeneous distribution of alloying elements. The distribution of alloying elements is more homogeneous in leading laser compared with leading arc, since both of the drag force of the plasma jet and momentum of droplet direct to the keyhole, promoting the inward flow in leading laser.