Abstract: Infant milk powder is the main dietary nutrition source for infants except breast milk, and its product quality directly affects infant development. Sixteen phthalates in infant milk powder were determined by using six deuterium labeled phthalates as internal standard. After a certain amount of deuterium was added into the milk powder, phthalate was dissolved in ultra-pure water, extracted with hexane, analyzed with gas chromatography-mass spectrometry and determined with internal standard method. The linear relationship of 16 phthalates was good in the range of 0.02 μg/mL to 1.0 μg/mL, and the correlation coefficients were all greater than 0.999. The recovery was 90.8%-103.6% in the range of 0.05 μg/mL-1.0 μg/mL and the relative deviation was 0.51%-3.75%. The effect of matrix effect on detection is eliminated and the recovery of detection method is improved.