The surface temperature of asteroids is a key parameter in studying the thermophysical properties of planets. The study of orbital dynamics of small and medium-sized celestial bodies in the solar system has a variety of practical applications, including predicting the orbit of planetary bodies and the cratering rate caused by impact and selecting appropriate detection and sampling targets for spacecraft. For NEAs, it is significant to analyze their orbital structure, orbital evolution, and future offset trajectory of Neos［1］. China is about to launch “tian wen-2” to detect the thermal radiation and sample the weathering layer of the near-Earth Asteroid 2016HO3. “Tianwen-2” is expected to reach orbit around 2016HO3 shortly. this paper studies a temperature-specific emissivity separation algorithm, which is used to extract the radiance data from the “Osiris Rex” thermal radiation spectrometer (OTES), Calculate the surface temperature of the planet "Bennu" with similar thermophysical properties to the asteroid 2016HO3［2］. The temperature emissivity separation algorithm combines the emissivity normalization method (NEM), ratio method (rat), and emissivity maximum-minimum difference method (MMD). It is a surface temperature inversion algorithm with high accuracy at present. To verify the algorithm’s accuracy, this paper uses the spectral data of the CRISM spectral library to study algorithm’s sensitivity to the target temperature and the band. Among them, due to the limitation of the instrument and other reasons, there is no error derivation of the length of the wave band. The results show that: (1) set the temperature range to 115~ 415 K and the step size to 5 K. With the increase in temperature, the root means square inversion error temperature increases and the error of emissivity is roughly unchanged. (2) The sample temperature is 295 K, and the starting point of the band used by the algorithm is 7.5 μ m. Sampling interval 0.04 μm. The endpoint is 10~13.8 μm. Step 0.2 μm. It is found that the wavelength range is 7.5~13.8 μm. The MMD module of the algorithm has the highest accuracy. The algorithm is used to solve the surface temperature of the planet “Bennu”. The results show that the average error of the temperature calculated by the algorithm is -0.366 0 K, and the standard deviation is 1.039 3 K except for pixels with large solar altitude angles and in high latitudes.