Abstract: Based on changing surface tension according to different chemical bond energy of oxides in flux-core,the effect of composition and content of flux oxides in self-shielded flux cored wire on welding spatter was investigated,meanwhile droplet transfer and spatter of wire by high-speed camera.The results indicated that the surface tension depended on the oxides composition and content in flux and had an important influence on droplet transfer characteristic,then effected welding spatter.Spatter by repelled transfer with small drop occurred when the surface tension was small,explosive splash by short circuiting transfer occurred when the surface tension was big.Under this experimental condition,the surface tension can reach the best value by adjusting the content of rutile,zicon sand and magnesium aluminum powder in flux-cored when the spatter loss coefficient reached minimum and blasting spatter of transition liquid bridge with arc bridge occurred.