Response of the location of the liquid/solid interface to processing parameters （cooling distance and pulling velocity） in OCC （ohio continuous casting） was expounded. The physical and mathematical models were established based on heat transfer in OCC process to obtain response function of location of liquid/solid interface to different cooling distance and pulling speed. Response ability of the location with varying in cooling distance and in pulling speed was simulated by the model. The results reveal that adjustment of cooling distance is prioror in the closed-loop control of the OCC process.