Abstract: Many kind of milk powders are treated by microwave dissolution technique with different operation parameters in this experiment． In order to seek the optimum digestion condition of the sample， Orthogonal test is used． A quantitative determination method of calcium in milk powders using flame atomic absorption spectrometry is established， which is easy and time－saving． This method avoids the losses of calcium during the pretreatment．The experiment recovery is 93．3％，and the precision is 1．91％．

Key words: Orthogonal test Microwave digestion FAAS Misk powder Calcium