Abstract: Ln this work,the fluid flow field in a bath caused by imping gas jet are studied by means of experiment with a physical model together with numerical solution of the mathematic model. Velocity distribution of the fluid flow in the bath is measured by laser Doppler anemometer. The mathematic model consists of the kinematic and dynamic equations of turbulent flow,one equation model of turbulence and newly defined boundary equa tions. The mathematic model is numerically solved implicitly using method Solving recirculating flow problems developed by Prof.Spalding, so that, the flow pattern,the distribation of velocity,vorticity,turbulent kinetic energy, and turbulent viscosity are obtained.The results computed agree well with those measurd in experiments.