Abstract: Abstract: In order to study the migration of Zn from low-density polyethylene (LDPE) films modified with nano-ZnO, according to the European Union regulation NO. 10/2011, distilled water, 30 g/L acetic acid, 95% ethanol (v/v) and 10% ethanol (v/v) were chosen as the neutral, acidic, fatty and alcoholic food simulants, respectively. Nanoparticle modified films (NMFs) were prepared by blending LDPE with nano-ZnO. Film characterization was conducted by transmission electron microscope (TEM) and the migration of Zn was measured by ICP-MS (inductively coupled plasma - mass spectrometry). Migration tests of Zn into 4 kinds of food simulants were performed under 40 ℃ for 2 h, 1 d, 4 d and 7 d, as well as 70 ℃ for 2 h. The effect of different temperatures on the migration was studied. Moreover, the influences of microwave and ultraviolet treatment were also studied. The size of nano-ZnO was observed to be about 100 nm in TEM image. This result indicated that particles in the NMFs still possessed nano size. It was obvious that NMFs had relatively higher content of Zn compared to the control in all kinds of food simulants. For NMFs in neutral simulant, the migration amount of Zn in 40 ℃ for 7 d was 10% higher than that in 40 ℃ for 1 d. While in acidic simulant, the migration amount of Zn in 40 ℃ for 7 d was 31% higher than that in 40 ℃ for 1 d. Migration amount of Zn in 40 ℃ for 7 d were 4% and 9% higher than that in 40 ℃ for 1 d, respectively, in alcoholic and fatty simulants (P<0.05). Results showed that the highest migration amount of Zn was in acidic simulant, followed by neutral, fatty and alcoholic simulants. The amounts of migration rose with the increase of temperature. In neutral simulant, the migration amount of Zn in 70 ℃ for 2 h was 1 245% higher than that in 40 °C for 2 h. When in acidic simulant, the migration amount of Zn in 70 ℃ for 2 h was 1 047% higher than that in 40 °C for 2 h. Migration amounts of Zn in 70 ℃ for 2 h were 902% and 1 524% higher than that in 40 ℃ for 2 h in alcoholic and fatty simulants, respectively (P<0.05). Microwave treatment could promote the migration. In neutral simulant, compared to the control, microwave treatment of 250 and 600 W increased the migration amount of Zn by 22% and 53%, respectively. While in acidic simulant, migration amount of Zn was enhanced by 22% and 53%, under microwave treatment of 250 and 600 W, respectively (P<0.05). However, ultraviolet treatment could not promote the migration of Zn. The amounts of Zn migrated into food simulants ranged from 0.52 to 14.17 mg/kg. The highest migration amount of Zn was beyond the limitation of 5 mg/kg in the European Union regulation No.10/2011. The results of migration test indicated that LDPE films modified with nano-ZnO might not be a kind of safe food packaging film, and it still needs further investigation.