Abstract: Using Fluent software to solve the Navier-Stokes equations, the effects of sister hole injection on both the film cooling effectiveness and the surrounding temperature field were studied with Realizable k-ε turbulence models under three angle conditions, namely 30°, 45° and 60°. Results show that the film cooling effectiveness with injection from sister holes is improved by interaction of vortices from two secondary holes and a main hole, which pulls the jet center that has been raised to the crosswise direction, damages the counter-rotating vortex pair, changes the lift force to transverse tensile force, so as to maintain the flow adhesion and improve the transverse distribution of coolant. The highest film cooling effectiveness is to be achieved at an angle of 30° between two sister holes.