The work aims to investigate the fresh-keeping effect of chitosan and sodium dehydroacetate coating on the betel nut based on modified atmosphere storage (the volume fractions of O2 and CO2 are 4%), with betel nut as the experimental material. The betel nuts were coated with chitosan solution of different mass fractions (0, 0.5, 1.0, and 1.5) combined with 50 mg/L (mass concentration) sodium dehydroacetate. The sensory quality, rot rate and nutritional quality of betel nuts during the modified atmosphere storage were tested. The quality of coated betel nut was significantly better than that of uncoated betel nut. The betel nut coated with chitosan (0.5%)/sodium dehydroacetate (50 mg/L) can maintain good product quality during the 30 days storage period and delay the yellowing of the peel.