Abstract: A full scale water model of continuous casting was built to investigate the effect of solidified shell on fluid flow and level characteristics under high speed casting. It is found that a slight asymmetry of fluid flow occurs in the model with solidified shell. Furthermore, the average level fluctuation and the meniscus velocity of the mold with solidified shell is 31% and 35% larger than those without solidified shell at a high casting speed of 2.4 m·min^-1, respectively. The deformation of the top level profile of the mold with solidified shell is also larger than that without solidified shell, which can be vulnerable to slag entrapment. In addition, the fast Fourier transformation analysis of level oscillation shows that the amplitude of high frequency fluctuation in the mold with solidified shell is larger than that without solidified shell due to a narrower space in the lower part of the mold, indicating that a more turbulence energy exists in the upper recirculation zone than that without solidified shell and thus results in a higher level fluctuation and a larger surface velocity. So taking solidified shell into consideration is necessary to minimize the difference between the model and actual steel casters.