Abstract: Rotational spray transfer,which is a main model of metal transfer in high-current MAG welding,is researched by a high-speed camera system.An instant unstable transfer phenomenon is found:there is an occasional non-axial repelled transfer in rotational spray transfer.This is a kind of interference in steady rotational spray and will produce spatter.Mechanisms of the phenomenon are discussed through theoretical calculating.As a result,the disappearance of the liquid cylinder at the tip of wire is the prerequisite of this phenomenon.Spot force and reactive force of metal vapor are responsible for the droplet buckling and turning over.The plasma stream force will lead the difference of repelled transfer between high-current MAG welding and conventional CO₂ welding.