Aero-thermal optimization on multi-rows of film cooling over a flat plate has been performed to optimize the inclination angles. Hence three cylindrical holes with injection angles of ?, ?, and ? have been considered. The cooling hole has a 3 mm diameter and an inclined angle between 25 to 35 degrees. Numerical simulations were performed at a fixed density ratio of 1.25 and blowing ratio of 0.5. The control-volume method with a SIMPLEC algorithm has been used to solve the steady-state RANS equations with SST k-? turbulent model. The injection angles of the holes are selected as the design variables to perform the optimization of three rows of film cooling. In order to evaluate the performance of holes arrangement, two objective functions are defined based on aerodynamic losses and adiabatic film cooling effectiveness. The curve fitting method (CFM) is used to find the optimal point of objective functions. The optimizations have been performed using the genetic algorithm (GA) method. Results of the present study show that the best performance of three rows of cooling holes was achieved in inclined angles 25.45, 32.85 and 33.1.