Abstract: A conjugate heat transfer simulation was conducted on the film cooling flow field at the trailing edge of gas turbine blades, and the simulation results were compared with that of adiabatic method, thus finding the film cooling behavior at different blow ratios and suction surface thickness. Results show that compared with the adiabatic method, the curve of film cooling efficiency obtained by conjugate method is more gentle, with more uniform temperature distribution on the suction surface but a higher temperature gradient above the pressure surface. Increasing the blow ratio could reduce the effect of heat conduction on film cooling and inhibit the separation of the fluid from wall surface effectively. As the thickness of the suction surface increases, the fluid temperature in the area from 0.6 to 0.76 isotherm changes, the temperature rises in the downstream of cutback outlet and decreases in the place far from the cutback.