Abstract: Calculation for two dimensional flow and heat transfer of impingement in a semicircular closure has been completed with a Finite Element Method.It is found that the impinging flow in closure is much different from the impingement in free space.Except the circulations on the two sides of inlet nearby the inner wall,it is possible to induce two contrary circulations nearby the out wall in down stream.The effects of the currents on isotherm and heat transfer are given graphically.