The effects of both the interphase convective interaction and radiative energy transfer on the spectra of temperature fluctuations are considered for homogeneous and isotropic turbulence in high-temperature, two-phase flow. The analysis is carried out for two kinds of small particles (with low Reynolds number), mainly scattering sapphire particles (Al2O3), and strongly absorbing coal particles. The radiative properties of the particles was calculated using Mie theory. Particles may modify the temperature spectrum of the carrier fluid by smoothing the intensity of temperature fluctuations. This effect is increased with a decrease of particle relaxation time and with an increase in particle concentration. At high temperatures, the presence of absorbing and scattering particles greatly increases the total dissipation rate due to two mechanisms : i.e. interphase convective interaction and radiative transfer. As a result, radiation modifies the spectrum of temperature fluctuations significantly, and increases the suppression of temperature fluctuations by the particles. Effects of radiation are different in various regions of wave space and depends as well on the radiative properties of particles and their concentration.