Through the application of mathematical modelling and water model experiments, a reasonable understanding has been obtained of flow pattern and mixing characteristics in ladle injection metallurgy. It is seen that the flow pattern in gas-stirred cylindrical vessel produces a recirculating vortex located high in the vessel and displaced toward the side wall. Stagnant zone is existing especially at the bottom of the vessel and increased as the H/D ratio is decreased. Mixing time of gas-stirred system is measured by means of a conductivity method. It was found that the time required for the homogenization of the tracer could be readily correlated with the rate of disspiation energy or Froude number. Mixing time also depends on geometry of a vessel. As the H/D ratio of a vessel is decreased, the mixing time is increased. The increase of mixing time in case of low H/D ratio is considered to be the increase of stagnant zone in bottom region.