According to the deficiency of temperature and emissivity separation(TES) model,a modified method of TES was presented.Simulated data were used to compare the precision of temperature and emissivity retrieved separately from before and after model modification.The sensitivity of TES and MTES model to the variety of initial setted emissivity,calibration error of atmospheric upwelling,downwelling radiation and transmission was then analyzed by way of theoretically analysis and simulated computation.Results show that the retrieval precision of MTES model is higher than that of TES model.Except for the calibration error of atmospheric downwelling radiation,other errors affect the precision of the two models,but MTES model is less sensitive to these errors.