A numerical study was conducted to investigate the effects of variations in cooling hole shape on film cooling performance. The injection angle and shapes of the cooling holes were designed with 30° injection angle, cylindrical shape and swirling hole shape with various pitch configurations. Film cooling effectiveness was compared under blowing ratios of 0.5, 1 and 1.5. The flow sturctures and characteristics were analyzed. The results show that as blowing ratios increases, swirling flow promotes coolant reattachment to the surface and mitigates lift-off tendencies, thereby improving film cooling effectiveness. And swirl strength has a significant influence on film cooling performance. Compared to conventional cylindrical holes, pitch 10 swirling hole shape improves in area-averaged cooling effectiveness by 4.36% and 9.52% at blowing ratios of 1 and 1.5, respectively.