Abstract: Reflectance spectroscopy was used to measure the near-infrared reflection spectra of cotton fabrics dyed with vat dyes with different structures,and the reflection spectra measured were respectively compared with that of the green leaf,investigating its camouflage mechanism.The results disclose that the reflective spectral line of the cotton fabric dyed with the vat dye is similar to that of the green leaf and the wave peaks of dyed fabrics vary with the kinds of vat dyes,i.e.the near-infrared reflection spectra of the dyed cotton fabrics are determined by the structure of dyes,mainly by the dye which has the maximum red shift.