In the process of applying Fluent software on the numerical analysis simulation of the subway air-conditioning and ventilation system, the designer of air-condition engineer may encounter many problems, such as repetitive work, demanding higher fluid professional knowledge and so on, but in this paper through using Visual Basic, the high-level programming language, compiler parameterized simulation system and invoke Journal parameterization log file can solve those problems. Using Journal parameterization log file is the most important method in the secondary development of the Fluent, not only can make the work more efficient but also can reduce the threshold of the user. The research includes three aspects. First, this research especially puts focus on the command stream file writing method (Journal file) of the software Gambit and Fluent. Second, according to the inputed parameters, the Gambit and Fluent software can automatically build the car body model, conduct numerical simulation calculation and save the Post-Processing Results. The last one, In the process of computing the Journal file of Fluent software can flexibly implement the related functions of CFD analysis, and realize the calculation analysis results compare with the experimental data. On the practical engineering the secondary development of Fluent has a very broad application prospect.