This paper presents a structural dynamic model with which temperature-dependent vibration characteristics of rotating blades made of functionally graded materials (FGMs) are investigated. Material properties are assumed to be temperature dependent, and vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. Temperature dependency of thermal conductivities was considered to obtain a non-linear steady state solution to the heat transfer equation for the blade under high external temperature and low internal temperature due to cooling passages. To derive the equations of motion, hybrid deformation variables are approximated using the Rayleigh-Ritz assumed mode method. The accuracy and efficiency of the proposed model was verified through a comparison study first. Then, effects of the volume fraction index, external gas temperature, coolant temperature, rotor angular speed and taper ratio upon the temperature distributions and natural frequencies of the FGM blade were investigated using the proposed model.