According to the multiple-instrument characteristics of the Terra（EOS） satellite.A multiple-channel algorithm was proposed to retrieve land surface temperature and emissivity from ASTER/MODIS data at the same time.That is

at first

four thermal bands（11

12

13

14） of ASTER were utilized to build radiance transfer equation.After analyzing the characteristics of the emissivity in ASTER TIR

the parameter emissivity is described approximately as two linear equations.Thus

the multiple-band algorithm retrieving LST and emissivity from ASTER/MODIS data comes into being after uniting four radiation transfer equation and the linear equation of emissivity.The key parameter transmittance is obtained from retrieved water content of atmosphere through NIR bands of MODIS.Because ASTER and MODIS data are on the same satellite

the transmittance was timely obtained.