Abstract: In this paper, a new filling strategy for multi-pass welding, which can be used in robotic welding, is put forward. By analyzing the shapes of the across areas of various kinds of beads in one joint, this paper gives out a build-up and welding sequence for V groove that the number of beads in a certain layer is equal to the ordinal number of the layer. With the equal across area of each bead in one joint, we work out that there is the equal layer height in the later layers from the second layer. So the filling strategy which plans the number of layers and the number of the beads in each layer for a V-type joint is presented. Using this filling strategy, the across areas of each beads are equal and the welding parameters are invariable. It overcomes the shortcoming of the filling strategies used before,in which welding parameters alternate frequently and are difficult to program. The welding test shows that the filling strategy could ensure the better quality of the joints.