Oxidation reaction of trans-anethole with oxygen was investigated at low temperature. The oxidation characteristic and pressure of trans-anethole were determined using a self-designed mini closed pressure vessel device. Peroxide concentration was measured by iodimetry, and constituents of oxidation products was detected by gas chromatography-mass spectrometry (GC-MS). Results showed that trans-anethole oxidation occurred in three stages: first, oxygen was absorbed slowly, then trans-anethole oxidation reaction became rapid, finally, oxidation process went to end. Trans-anethole absorbed oxygen，followed by the generation of anethole peroxide. Peroxide concentration was influenced by reaction condition, and peroxide concentration reached the maximum (85.07 mmol/kg) at 95℃ 4h. The oxidation products were complex, including anisaldehyde, acetaldehyde, anethole epoxide, anethole diol and P-anisil, and the selectivity of anisaldehyde is 70.36% at 55℃.