Fluent calculation is an important means to simulate the flow of molten iron in blast furnace hearth. However, Fluent has many problems such as complicated operation and difficult entry and so on. By using Microsoft Visual Studio (VS) to develop the Fluent again, log file(Journal file) coded by TUI(Text User Interface) is used as the interface between VS and Fluent to interact data, and to establish geometric model of the flow of hot metal in blast furnace hearth based on many main parameters, such as hearth diameter, hearth radius, iron mouth depth, taper angle, and dead column state to optimize the process of parameter transfer. Modifying and replacing parameters of the log file with the method of variation replacement, which drives Fluent to achieve the model of the flow of hot metal in blast furnace hearth and simulate the stream field. The application software matches with practical engineering and it has simple and friendly interface, which reduces the use requirement of Fluent for the users and improves the work efficiency, and enhances the versatility and fastness of Fluent in the blast furnace industry.