The work aims to achieve convenient and efficient preservation of chestnuts. Bleached shellac with different mass fractions of hydrophobic substrate was mixed with sodium alginate as a hydrophilic substrate, and a preservative potassium sorbate was added to prepare a composite coating preservative for the storage and preservation of chestnuts. Changes in physical and chemical indexes and nutritional components of chestnuts during storage were monitored. The results showed that coating treatment at room temperature reduced the weight loss rate, moldy rate, insect fruit rate, and calcification index of chestnuts, while also reducing the respiratory intensity of chestnuts and slowing down the consumption of nutrients such as starch and vitamin C. The composite coating with a mass fraction of 7% bleached shellac and 1% sodium alginate had a better preservation effect on chestnuts. On the 25th day of storage, the weight loss rate, moldy rate, and insect fruit rate of the treated group were reduced by 44.00%, 56.20%, and 63.88% compared with the blank control group, respectively. The starch content and vitamin C content were increased by 28.84% and 11.16%, respectively. Bleached shellac/sodium alginate composite coating could reduce metabolic consumption during chestnut storage, maintain storage quality, and reduce nutritional loss. This study provides a scientific basis for the development of chestnut coating preservation technology.