Abstract: The film cooling technique is one of the useful cooling methods.At present,the sparse film cooling technique is alaiays employed for the midchord region of gas turbine blade in aeroengine,and the impingement cooling technique is also used at the same time.So the interior heat transfer characteristics about an inner side of blade due to sparse film cooling holes have become a very complicated and interesting problem.In this paper,the heat transfer characteristics have been investigated experimentally whether there is impingement cooling fluid or not.Through lots of experimental data,the effect of flow parameters and geometric parameters on heat transfer characteristics has been studied.Besides that,the correlation equation for the interior heat transfer characteristics to the parameters is finally formulated,and the comparison shows that the correlation results are in good agreement with the experimental data.