The aim of this paper is that studies on the characteristics of the liquid-gas ejector. We could get data about various models using numerical analysis. Compare and analyze results that get by an experiment and numerical analysis. And study characteristic of the ejector. In this paper, Numerical analysis model is gotten divided according to each Throat ratio as three types. Each throat ratio is 0, 4 and 7.5. And other CFD geometric is created by nozzle position in ejector. Nozzle positions represent by 2d, 3d, 4d and 5d respectively. According to the result that analyze basic model, pressure became lower causing the volume flow rate increase. In CFD studies, Fixed volume flow rate by these result and analyzed ejector performance. As a result, there was no change of pressure to Throat's Entrance, and pressure became low while pass the throat. Since, pressure recovered while passing diffuser. The outer flow velocity did not change greatly to change of volume flow rate. This research expects that is utilized to data for performance elevation hereafter.