Film cooling effectiveness on the leading edge with one row of holes is studied experimentally.The model was a blunt body with a half cylinder leading edge and two flat plates.One row of holes was located at the place 2 hole pitches from the stagnation line.Foreign gas injection was used to obtain a density of approximately 1.5.High turbulence intensity was produced by a passive grid.Momentum ratios varied from 0.5 to 4.The result indicates that film cooling effectiveness decreases with increasing momentum ratio.Spanwise averaged film cooling effectiveness is reduced by high mainstream turbulence intensity with momentum ratio of 0.5 and the mainstream turbulence effect is diminished with increased momentum ratio.Film cooling effectiveness along the film cooling hole is significantly reduced by high mainstream turbulence level.Spanwise averaged film cooling effectiveness decreases in the case of low momentum flux ratio and spanwise averaged film cooling effectiveness increase in the case of high momentum flux ratio because of foreign gas injection.