Since high chromium cast iron forms high hardness Cr7C3 carbide, it has high wear resistance and it is used for heavy equipment parts and hot working rollers. Hot working rollers are manufactured by casting. However, the problem is nonuniformity of solidification structure and macro / micro segregation due to convection phenomenon of cast iron. In this study, we observed high temperature samples and the flow field of high chromium cast iron using CLSM. As a result, the formation of solidification structure influences in flow direction and moving speed of sample surface. In addition, it is possible to capture micro segregation formation process of high chromium cast iron from in situ observation by CLSM and average slag moving.