The work aims to solve the excessive release problem of essential oil in antibacterial fresh-keeping packaging and achieve its sustained release by means of the microfibrillated cellulose (MFC) aerogel which has high porosity, large specific surface area and good adsorption performance combined with thyme essential oil. The pretreatedment of eucalyptus bleached kraft pulp was carried out with different dosages of endocellulase and high pressure homogenization was used to prepare MFC. MFC aerogel was prepared by freeze drying, and the sustained release properties of its essential oil were studied based on the basic performance characterization. GC-MS analysis of thyme essential oil showed that, the main antibacterial component of it was thymol. MFC aerogels were of a three-dimensional porous structure. The specific surface area of aerogel varied from 2.0 to 5.1 m2/g, and the average pore size ranged from 5.0 to 22.0 nm. When the essential oil: MFC mass ratio was 1∶1, the initial retention rate of essential oil of MFC aerogel was 4.38 mg/g (4.38 mg essential oil remained in per gram of aerogel), and the amount of essential oil released to the sealed container showed a trend of increasing first, then decreasing and gradually stabilizing with the average release rate of 3.1%. MFC aerogel is a kind of mesoporous material of high porosity that can prolong the release time of essential oil and has excellent sustained release properties.