Michler's ketone is widely used in food packaging cardboard manufacture. However, Michler's ketone was proved to be human carcinogens. Testing and migration of Michler's ketone and related aromatic amine from food packaging cardboard materials was studied with liquid chromatography (LC) method. Polyethylene-coated and non-coated cardboard samples were put into food simulants to evaluate the migration of Michler's ketone. Water, 3% acetic acid, 10% ethanol, and 95% ethanol were selected as food simulants. Stability test was carried out on other aromatic amines related to MK. The results showed that MK degraded obviously in acidic water solution. It was concluded that MK is a potential migrant in food packaging materials, because it can be generated from degradation of many purple dyes or pigments through chemical or photo degradation.