A computer program for calculation of the solidification process of steel with the fluid flow in 2-D cylindrical system was developed. TEACH-2E source program of Patankar et al. was modified to simulate the solid-liquid two phase phenomenon. In this study it was treated as one phase. The energy equation was solved by modifed heat capacity method and the momentum equation by giving effectively large viscosity to solid phase. From this method the fluid flow and temperature profile could be obtained. It was found from this study that fluid flow patterns during filling of motten metal were hardly changed by Gr number and the transition from forced to natural convection was completed within 5∼13 minutes after pouring. When convection effect was domimnt, the planar solidlfication started to occur from the bottom of the mold and It was found that the greater the Gr number, the faster the solidification process.