Ejectors are simple pieces of equipment. They are employed in the industry such as in refrigeration and air conditioning, desalination, petrochemical and chemical industry. The purpose of this paper is to reveal the complication of the flow and the mixing process in a steam ejector. Air was used as primary and secondary fluids here. In this study CFD simulation were also undertaken. On the experiment, the influence of operating condition and nozzle exit positions were investigated. The result shows the static pressure distribution along the ejector wall is influenced by the motive pressure and nozzle exit position. Standard k-epsilon, RNG k-epsilon, and Realizable k-epsilon were tested in CFD. The CFD results were validated with available experimental data. The result shows the Realizable k-epsilon model more coincide with experimental than the other models.