Characteristics of atmosphere and emissivities are the major influencing factors in land surface temperature retrieval.Different split window expressions can result in different retrievals of land surface temperature.Among them,the split window algorithm with linear combination of two channels' radiance has the least atmospheric influence.Retrieved temperature errors are correlated with emissivities and downwelling atmospheric radiance,not correlated with transmittance and upwelling atmospheric radiance.Retrieved coefficients(a and b) of split window method(B(λ′,T~°_s)=a·I(λ_1)+b·I(λ_2)+c) have not relations with upwelling atmospheric radiance,but have inverse ratio with transmittance of two channels,respectively.When the land surfaces for calibration have different emissivities,the retrieved coefficients a and b have relations with downwelling atmospheric radiance,however,if the land surfaces for calibration have the same emissivities,the retrieved coefficients a and b will bear no relation to downwelling at