The shell distribution in the slab continuous casting mold has been simulated coupling a 3-D flow, temperature and volume fraction equations of the molten steel in FLUENT. The simulated results show that the flow velocity around the upper vortex center is decrease and the location of lower vortex center move down as the nozzle port angle increases. The simulated shell thickness in the center on the narrow face become thicker at meniscus and the shell thickness in the center on wide face decreases but the basic distributions of the shell tend to consistency as the nozzle port angle increases. The simulated results also show that the effects of solidified shell on flow field in mold is slight but the velocity of molten steel near the solidified shell. There are remelting near the impact regoins implicit our attentions in order to avoid breaking out.