Dust aerosol can cause the change of the land surface temperature(LST) by altering the thermal infrared radiative transfer of earth-atmosphere system. The influence of different winter and summer dust aerosol optical depth (AOD) on thermal infrared brightness temperature(BT) and LST retrieval was systematically studied and the inversion results influenced by water vapor in the atmosphere and surface factor were also studied. Thermal infrared radiative transfer calculation indicates that 1.brightness temperature difference is less than 0 under the influence of dust aerosol; 2.BT and LST decrease with the increase of AOD, in which the decreasing trend of LST is more obvious; 3.LST changes very little with different water vapor content; 4.LST mainly reflects the temperature of dust layer for bigger AOD. These results agree well with the instance analysis of typical dust in the north of China.