The titanium reduction from titanium tetrachloride (TiCl4) by molten magnesium pool, called the Kroll process, is regarded as a well-known process for the commercial-scale production of titanium sponge. Purified titanium tetrachloride vapor reduced by magnesium, forms sponge titanium with generating excessive heal. The heal transfer phenomena in a Kroll reactor should be thoroughly understood for productivity and quality enhancement. In this work, a computational modeling method to describe the thermal behavior in the TiCl4 reduction reactor was investigated and validated with the measured temperature distribution in a 500kg titanium sponge-capacity pilot-scale reactor in terms of various reduction ratios. The approach model for heat flow phenomenon in a reduction reactor could be utilized as a tool to predict the influence of operating process parameters on the optimization of Kroll process.