Abstract: Detailed experimental measurements of the flow fields around a row of short cylinders with jet impingement by using a five hole probe have been conducted.The three dimensional velocities and vortex distribution were demonstrated and studied.The experimental data show that the largest velocity was observed at the place very close to the cylinder surface,velocities decreased rapidly in lateral direction from the surface to the symmetric plane of the channel where low velocity flow was found together with reverse flow and vortex.Endwall effect and flow separation result in strong vortices in cylinder array.Interaction of cylinder and endwall boundary layer produces horseshoe vortex at the root of the cylinder.In the wakes turbulent vortices exist.The lateral variation of pressure leads to the producing of channel vortex.As compared with the flow field without jet impingement,the angular position of separation on the surfaces of cylinder moved downstream and the width of wake was reduced obviously.