Abstract: A qualitative and quantitative analysis model for adulterated infant milk powder was established based on mid-infrared attenuated total reflectance（ATR）spectroscopy. Forty pure milk powder samples were prepared, and adulterated milk powder samples（the mass concentrations were 0.1%-30% for starch and 0.1%-40% for flour）were prepared. The mid-infrared ATR spectra of all samples were collected. The identification model of adulterated milk powder was established by combining mid-infrared spectroscopy and partial least squares, and the accuracy of identification for unknown samples was 94%. Finally, the spectra in the range of 962-1 122 cm^-1 was selected to establish the quantitative analysis model of starch in adulterated milk powder. The spectra in the range of 3 522-3 362 cm^-1 and 1 282-800 cm^-1 were selected to establish the quantitative analysis model of flour in adulterated milk powder. For starch, the correlation coefficient R of prediction model for the unknown sample was 0.98, and the root mean square error of prediction（RMSEP）was 0.062. For flour: the correlation coefficient R of prediction model for the unknown sample was 0.99, and the RMSEP was 0.032.

Key words: infant milk powder, mid-infrared spectrum, starch, flour, qualitative and quantitative analysis