In this study, numerical simulation by using computational fluid dynamics (CFD) codes were conducted to investigate the influence of alternative layouts for air distribution in a full scale newly constructed data center. Through the simulation of different airflow distribution patterns in the data center, the optimum practice for cooling airflow arrangement can be identified easily. The simulation results also revealed that the best practice with a vertical under floor cooling architecture can provide satisfactory airflow distribution and thermal management. Higher cooling performance can be achieved by providing better separation of cold and hot aisle stream. Rack cooling index (RCI) has been used to evaluate the cooling performance of environmental conditions for the data center facility. Numerical study through CFD simulation can not only identify the best practice for airflow distribution, but also provide the energy-efficient and cost-effective HVAC system specific for data center facility.