To improve film cooling effectiveness of a gas turbine blade, a kind of plasma actuator is introduced on the blade surface. The effect of three arrangements of plasma actuators on flow characteristics and film cooling performance is numerically investigated by a verified turbulence model. Results show that the coolant air under plasma is pulled down to the wall, and the near-wall air is sped up to promote the film cooling effectiveness downstream the wall. It is discovered that the plasma actuators near the film hole show weaker aerodynamic actuation than that downstream the wall. Compared with the plasma actuators off case, the maximum improvement in the wall-averaged film cooling effectiveness of the case with up plasma actuators is 11.7% under low blowing ratios. The wall-averaged film cooling effectivenesses of the cases with down plasma actuators and up-down plasma actuators increase by 138.3% and 122.9% under the blowing ratio of 1.5.. Vortex structures are broken up, and vortex is separated by two jets induced by aerodynamic actuation. The maximum wall pressure difference reaches 1.89% when plasma actuator is arranged downstream the wall.