In order to determine the relationship between the well width and the peak wavelength of quantum well infrared photode tector (QWIP),the detailed structure parameters of two sample devices based on t he bound to the quasi bound state transitions (b-qbQWIP) are designed and corre sponding tests such as spectroscopic response and photoluminescence (PL) spectra ,are done.The GaAs/Al0.3Ga0.7As infrared quantum well materials with different structure parameters has been grown by using metal organic chemical vapor deposition (MOCVD).The spectroscopic response is measured at 77K by Fourier transform spectrometer,while the photoluminescen ce (PL) spectra are tested at room temperature for two sample devices of GaAs/Al0.3Ga0.7As quantum well infrared photodetectors with well wid ths of 4.5nm and 5.0nm,respectively.Peak wavelengths of sample 1# and 2# are 8.39μm and 7.69μm from results,while the ones are 8.92μm and 8.05μm according to Schrodinger equation,and the error between them is 6.36%,4.70%,respectively.It is studied that the peak absorption shifts to high-energy region,which shows that it is t he strong stress but not the doping Si in well that leads to peak wavelength red -shift.The PL results are consistent with theoretical simulation.The increased well width leads to interband transition energy going up.Results show that changing well width c an adjust the peak wavelength of QWIP indeed.