Gas turbines are widely used in industry. The turbine inlet temperature of modern gas turbine engines has been increased to achieve higher thermal efficiency. However, the increased inlet temperature can result in material failure of the turbine system due to the higher heat transfer and induced thermal stresses.The leading edge of the rotor blade experiences the highest values of heat transfer coefficient That’s why the most conventional researches (including the present research) places film cooling holes on leading edge of blade. The cooling holes have been made at three parallel rows. The Gambit grid generation software was used to generate unstructured grids, with fine grid clustering near the wall. Computations have been followed upon the heat transfer coefficient of blades by Fluent to solve compressible Reynolds-Averaged Navier-Stokes equations.The results have been compared with experimental evidences. In compare with experimental data, Heat transfer coefficient shows a good agreement on pressure surface while the results on suction surface don’t seem satisfactory. The reason for this poor agreement could be placed on decreasing of pressure at suction surface that lead to instability of flow. Best predictions have been made by k-?-SST model and v 2 f model. At First, blades’ film cooling has been studied without motion. Then the effects of mass and temperature coolant have been followed. Secondly, rotary blades have been studied for the variations of mass coolant at three velocities. Temperature reduction of coolant doesn't have a great effect on heat transfer coefficient, but decreases the heat transfer coefficient in small areas on the blades’ pressure surface. Increasing mass coolant up to 1 percent of hot fluid, decreases heat transfer coefficient at most area especially at pressure surface. Also growth of mass coolant up to 1.5 percent of hot fluid increases heat transfer coefficient at some areas of suction surface near the leading edge which is because of expansion in turbulency near the holes. Variant of mass coolant has been studied with three flows at rotator status. Decreasing Heat transfer coefficient have caused raising mass coolant up to 1.5 percent of hot gas, Variations of mass coolant have been studied with three kinds of flows concerning rotator status. First of all, under low and moderate velocities, increasing mass coolant up to 1.5 percent causes a reduction on heat transfer coefficient. Second of all, concerning high rotation velocities we will have a reduction on the coefficient up to the 1 percent while proceeding to 1.5 percent put incremental changes on some parts of blade. Keywords: Film cooling, Gas turbine, Rotor blade, Heat transfer coefficient