This paper gave an overview of the past and present applications of various Computational Fluid Dynamics (CFD) methods for indoor environment modeling. Typical applications used the CFD to calculate airflow, air temperature, contaminant concentrations, and turbulence in enclosed environment for studying or designing thermal comfort and indoor air quality. With simple airflow and geometry, the CFD is capable of calculating accurately mean flow parameters but less accurately turbulence parameters. For airflow in real indoor environment, it is very challenging to measure and calculate accurately the mean and turbulence flow parameters, because neither of them are free from errors. Thus, a complete validation of the CFD results by the corresponding experimental data obtained on site is extremely difficult. In the future, CFD applications for indoor environment will deal with more complicated dynamic problems and will require a method for faster than real time simulations of airflow. The Fast Fluid Dynamics (FFD) can dramatically enhance the computing speed. By running the FFD on GPUs, it is possible to perform faster than real time simulations of airflow in indoor environment.