The comparison of different submerged entry nozzles(SEN)was made by numerical simulation regarding the influence of liquid steel flow field,heat transfer and mold fluxes,as well as solidification shell stress and surface quality of thin slabs.The optimum internal shape of mold and the SEN were obtained.The foundation for choice of internal shape and casting parameters of mold was built. The comparison of different submerged entry nozzles (SEN) was made by numerical simulation regarding the influence of liquid steel flow field, heat transfer and mold fluxes, as well as solidification shell stress and surface quality of thin slabs. the SEN was obtained. The foundation for choice of internal shape and casting parameters of mold was built.