Abstract: The sample was digested by microwave and the content of aluminum in pastry was determined by inductively coupled plasma mass spectrometry(ICP-MS).The uncertainty of determination method was estimated. The uncertainty sources for each of the parameters were analyzed and combined.When the content of aluminum is 77.6 mg/kg, the expanded uncertainty is 2.5 mg/kg(k=2).The method is suitable for the evaluation of uncertainty on the results obtained by using the linear regressive standard curve.