The GaAs/AlGaAs quantum well samples with 30~50period 300μm×300μm surface mesa,80μm×80μm external electrode pad area and 20μm×20μm inter nal electrode pad area were grown by metal organic chemical vapour deposition metho d (MOCVD).The peak response wavelength was 8.5μm.The spectral characteristics of the test samples were analyzed and discussed theoretically and experimentall y.Fourier spectrometer was used to test their spectral response at 50K liquid helium temperature respectively.The experimental results show that the peak re sponse wavelengths of 1# and 2# samples are 8.38μm and 8.42μm respectively, which are 0.12 μm and 0.08 μm different from the theoretical peak response wav elength of 8.5μm respectively,with an error of 1.4% and 0.9%.The error between the experimental value and theoretical value of the peak response wavelength of the two samples is less than 2.0%.The experimental results show that the metal organic chemical vapour deposition method technology can meet the requirements o f quantum well infrared material growth process.The size and location of the el ectrode pad area of the detector have little influence on the spectral character istics of the device.The error is mainly caused by the testing system.The micr ostructure of the samples is analyzed by using high-resolution transmission scan ning electron microscope (HRTEM),which shows that although the samples have dis location phenomena of different degrees,the stress and strain caused by the mis match between GaAs and AlGaAs lattices have no obvious influence on the macrosco pic spectral response characteristics of the device.