Because the dynamic soft reduction of continuous casting process is based on the computation of the solidification end point, using model to simulating the steel solidificating process is more and more interesting. Especially, the influence of the heat flux to the solidification end point is needed to research thoroughly. In this paper the heat transfer model for the simulation of the solidification of steel droplet is established. The simulation reveals that the steel droplet (the radium is 7.2 mm) is solidified quickly in 4.3 seconds on water cooling copper plate, and in 3 seconds there is half of the droplet is frozen to solid. If there are materials resisting heat transfer inserted between cooling plate and liquid steel, the solidification end position would be moved to the deeper place below the shell in obvious extent, and the influence of heat flux to the ratio of mushy zone is weaker than that to solidification end point position.