The new and advance technologies for higher performance and lower maintenance are required to operate the gas turbines at higher operating temperatures. Higher turbine inlet temperature results in higher blade metal temperatures. These variations in temperatures of the blade material must be limited such that the blades have a sufficient life span. To make blade material temperature within the limits the coolant air is bled from the compressor to protect the outer surface of the turbine blade from the hot gases. The purpose of the work is to investigate the cooling performance of blade with leading edge cooling holes. The numerical simulation approach using ANSYS Fluent has been considered. The analysis is performed by taking different hole geometries namely cylindrical (model 1) and tapered (model 2) on the leading edge of the turbine blade for different blowing ratios. The analysis also compares the cooling effectiveness of the blade for two different coolants namely air and nitrogen. Result shows, for highest effectiveness hole (E3 hole), the Model 1 and Model 2 comparison suggest that Model 1 has 1.2% more cooling effectiveness for air as coolant. For E3 hole comparison of Model 1 between two coolants show that film cooling effectiveness of air gives 0.6% more film cooling effectiveness compared to nitrogen. The article concludes that the presented work helps researchers and blade manufacturers to select the correct hole geometry, coolant type, and determine the best blowing ratio to improve the film cooling efficiency of gas turbine blades with leading edge holes.