The traditional method of measuring the aeroengine exhausts is intrusive gas sampling analysis techniques.The disadvantages of the techniques include complex system,difficult operation,high costs and potential danger because of back-pressure effects.The non-intrusive methods have the potential to overcome these problems.So the remote FTIR passive sensing is applied to monitor aeroengine exhausts and determine the concentration of the exhausts gases of aeroengines.The principle of FTIR remote passive sensing is discussed.The model algorithm for the calibration of FTIR system,the radiance power distribution and gas concentration are introduced.TENSOR27 FTIR-system was used to measure the spectra of infrared radiation emitted by the hot gases of exhausts in a test rig.The emission spectra of exhausts were obtained under different thrusts.By analyzing the spectra,the concentrations of CO2,CO and NO concentration were calculated under 4 thrusts.Researches on the determination of concentration of the exhausts gases of aeroengines by using the remote FTIR sensing are still in early stage in the domestic aeronautics field.The results of the spectra and concentration in the aeroengine test are published for the first time. It is shown that the remote FTIR passive sensing techniques have a great future in monitoring the hot gas of the aeroengines exhausts.