Abstract: Abstract: Nanoparticle usually has unique physical and chemical characteristics and has become attractive to researchers in recent years. Chinese hickory is well known because of its high polyunsaturated fatty acid (PUFA) content. However, high PUFA content limits the shelf life of the products due to the susceptibility of PUFA to oxidation. Lipid oxidation decreases economic value of walnuts during the storage. Oxidation resulting in an undesirable rancid taste makes Chinese hickory unacceptable for the consumer. Oxygen concentration is one of the most important environmental factors affecting lipid oxidation. Lipid oxidation can be inhibited by using packaging material with low oxygen permeability. Improving barrier properties through the use of nanocomposites is an important topic of research, especially for the food packaging industry. Nano-titanium dioxide (nano-TiO2) is a kind of nano metallic oxide which has been researched in some academic fields. Adding nanoparticles to the polyethylene (PE) could significantly decrease the oxygen, water vapor permeability and longitudinal strength, and inhibit spore germination. TiO2 has been the focus of photocatalysts because of its physical and chemical stability, low cost, ease of availability and non-toxicity. Nanoparticle composite material has revealed its importance in agricultural products preservation these years. In this study, nano-TiO2 modified low density polyethylene (LDPE) film packaging was prepared by blending LDPE with nano-TiO2. The effects of nanoparticle modified LDPE film packaging on both physiology and quality of postharvest Chinese hickory stored under 20℃ were investigated. During the storage the physical and chemical indicators included CO2 and O2 volume fraction in packing, oxidation value, hexanal, total fat, total soluble sugar, activities of peroxidase, lipoxygenase and lipase, total phenol and total tocopherol, which were detected every 30 d to determine the Chinese hickory quality. Results showed that most physical and chemical indicators of Chinese hickory in each group were significantly changed (P<0.05) during the whole storage time. Compared with the control group, nano-TiO2 modified LDPE film was more effective in forming high CO2 and low O2, delaying the increase of peroxide value and hexanal, slowing the decrease of fat, soluble sugar, total tocopherol and total phenols, and inhibiting the activities of peroxidase, lipoxygenase and lipase. After 180 d, O2 content of nano-TiO2 modified LDPE film was 36.36% lower and CO2 content was 7.25% higher than that of the control. The results indicated that nano-TiO2 modified LDPE film had low gas permeability (P<0.05). Oxidation value and hexanal content were respectively 35.03% and 41.21% lower than that of the control (P<0.05). Total fat, soluble total sugar, total phenol and total tocopherol were respectively 4.07% (P>0.05), 6.9%, 11.37% and 8.87% higher than that of the control (P<0.05). Activities of peroxidase, lipoxygenase and lipase were respectively 17.21%, 8.96%, and 20.55% lower than that of the control (P<0.05). All these were maybe due to the lower gas permeability of nano-TiO2 modified LDPE film. These results indicated nano-TiO2 modified LDPE film is effective in maintaining the quality and prolonging the storage life of Chinese hickory and has a potential application prospect in the packaging of postharvest Chinese hickory. This paper provides the reference for the application of nanoparticle modified composite film materials in the preservation of Chinese hickory.