The migration pattern of nonvolatile substance from plastic material to liquid food. Five kinds of plastic films commonly used in food packaging were tested. The linear relationship between total amount of nonvolatile and time were studied in different soaking liquids, under normal test conditions and extending soaking time up to 120 days. The results showed that the total amount of nonvolatile increases along with the increasing of soaking time; the amount of migration is most and the maximum 28. 5 mg/ L in 4% acetic acid; the amount of migration is least and the maximum is 20. 5 mg/ L in 65% ethanol; total amount of nonvolatile of A film in simulated immersion fluid for up to 120 days is 55. 5 mg/ L; the amount of migration is most and the maximum 95. 5 mg/ L in n-Hexane soaking liquid under extreme using conditions. Migration behavior of the five films was found in three soaking liquids, and damage would be assessed in the future.