Abstarct: Gas turbines require to increase the inlet temperature of the turbine in order to achieve higher thermal efficiency. Increasing the temperature leads to the inevitable heat load exceeding the endurance of the turbine blade alloys, which is essential for proper operation, cooling of the turbine blades. In this study, focusing on the performance of external cooling, the structure of the trench geometry was changed in order to increase the film cooling effectiveness and reduce the cooling flow detachment from the surface of the gas turbine blade. Three-dimensional simulation is performed using numerical methods. For validation, three different turbulence models have been studied and the k-ε realizable turbulence model has provided more accurate results and has been considered as the model used in this research. To improve the film cooling effectiveness of turbine blades, trenches with different geometry have been conducted under the same cooling conditions and at blowing ratios of M = 0.5, 1 and 2. In other words, in the simulation process, in addition to the simple transverse trench for validation and comparison of modeling results, the w-wave trench structure with three different amplitudes with downstream edge variations has been investigated. The utilization of w-wave trench structures weakens the counter-rotating vortex pair (CRVP), which is one of the factors causing the cool flow to rise from the surface and penetrate into the hot stream. Formal distribution of coolant flow and increase of heat shield on the blade surface leads to improved effectiveness and reduced surface temperature. Furthermore, baxsed on the information and results, the use of variable radius fillets (VRF) on the downstream edge of the w-wave trenches led in a significant improvement in cooling effectiveness in the lateral directions and along the hole centerline. In the examination of variable radius fillets enlargement, the w-wave trenches with longer amplitudes performed better than trenches with shorter amplitudes. In general, the w-wave trenches have a better performance at high blowing ratios and at blowing ratio of M=2, the average-lateral cooling performance in the best case of w-wave trench designs is about 23% and with variable radius fillets, about 39.6% Increased relative to the transverse trench. The results of laterally averaged heat transfer coefficient (HTC) ratio illustrate that increasing blow ratio and using VRF promoted the amount of HTC in the downstream surface. Furthermore, the use of VRF on higher amplitude w-wave trenches has yielded good results in NHFR than other geometries in all blow ratios.