A method for the simultaneous determination of Pb, Cr and Hg in milk was developed by microwave digestion combined with inductively coupled plasma mass spectrometry (ICP-MS). The sample preparation procedure, the ICP-MS parameters, the internal standard and the monitor isotope were optimized. The results showed that the digestion temperature was 180 ℃. A mixed solution of 10 μg/L 72Ge and 209Bi was selected as the internal standard to eliminate the matrix effect, and 200 μg/L Au was added to the solution to eliminate the memory effect of Hg. 208Pb, 52Cr and 202Hg were monitored with ICP-MS to determine Pb, Cr and Hg, respectively. Under the optimal conditions, detection limits of 5.0 (Pb), 1.0 (Cr) and 0.5 (Hg) μg/kg were obtained. The contents of Pb, Cr and Hg in 40 batches of commercial milk were low. The detection values were smaller than 0.011 mg/kg for Pb and smaller than 0.031 mg/kg for Cr. Only 1 sample was found to contain Hg, and the detection value was 0.008 mg/kg.