The expression of the solute distribution in columnar crystal zone was deduced when the solid-liquid interface bended periodically,and the quantitative calculations of macrosegregation were also made in the process of the continuous casting.The solute distribution along the thickness direction of the slabs was obtained,which verified the theoretical calculation.The effect of the bulge size,solidification speed,and solidification shrinkage speed on macrosegregation of the slabs was calculated.It can be concluded that normal segregation and negative segregation alternatively appear as a result of the bulge.The normal segregation exponentially depends on the bulge size,and the negative segregation linearly depends on the bulge size.The extent of the normal segregation is greater than that of the negative segregation when the bulge size is the same.The macrosegregation of the same position along the thickness direction of the slabs changes in a sine wave with increasing the solidification rate,and the amplitude is larger at the casting blank center.The normal segregation linearly decreases with increasing the solidification shrinkage speed,and when the solidification shrinkage speed exceeds a critical value,the segregation appears negatively and increases linearly.