Abstract: Turbulent flow structures downstream of the straight and curved cooling hole were measured by means of 2D PIV (Particle Image Velocimetry) at blowing ratios of 0.5 and 1, with a Reynolds number of 480, during which the mean velocity, vorticity fields and smoke visualizations were obtained on the central symmetry plane and four cross sections, while the influence of hole structure on development of downstream vorticity field analyzed along the flowing direction. Results show that compared with straight holes, the curved hole produces a lower jet trajectory, which helps to raise the adhesion force of cooling film to wall surface, and therefore improve the cooling efficiency; simultaneously, the curved hole provides stronger transverse momentum, which makes the curved jet transversely expand more and finally improves the transverse coverage of cooling film.