Abstract: The temperature, stress and flow distribution of a bloom in GCr15 steel were simulated based on a mixed Lagrangian-Eulerian method, and the simulated results are consistent with practical blooms. The corner temperature of the bloom shell is higher than the middle parts. The tendency of the bloom surface temperature from top to bottom decreases gradually. Moreover, the isothermal zones are similar to the change of flow fields. The middle thickness of the casting bloom shell is about 17.5 mm, and the corner thickness is about 13.2 mm. The stress in the solidification shell is mainly thermal stress. When the shell is just out of the mold, the outer surface is in a compression state, while the front of solidification is in a completely tensile state. The effective strain increases from the outer surface to the front step by step. The liquid steel expands and its velocity decreases gradually in the progress. When the flow arrives to a certain depth, there are two symmetric upward backflows and a backflow area is formed by the side of face solidification downward and the centre upward.