The aim of the present study was to investigate the effects of ethanol vapor on the inhibition of Alternaria alternata and Botrytis cinerea in postharvest blueberry and the induction of defense-related enzymes (DREs) activities in fungi-inoculated blueberries stored at 0±0.5°C for 16days. Results indicated that ethanol vapor markedly inhibited the mycelial growth of A. alternata and B. cinerea in a dose-dependent manner, with inhibition rates of 9.1% (250ÎŒlLâ1), 36.4% (500ÎŒlLâ1), and 5.5% (1,000ÎŒlLâ1) on A. alternata and 14.2% (250ÎŒlLâ1), 44.7% (500ÎŒlLâ1), and 76.6% (1,000ÎŒlLâ1) on B. cinerea, respectively. Meanwhile, ethanol vapor also enhanced the activities of DREs in fungi-inoculated blueberries, including ÎČ-1,3-glucanase (GLU), chitinase (CHI), phenylalnine ammonialyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO). In particular, 500ÎŒlLâ1 ethanol vapor increased the activities of DREs by 84.7% (GLU), 88.0% (CHI), 37.9% (PAL), 85.5% (POD), and 247.0% (PPO) in A. alternata-inoculated blueberries and 103.8% (GLU), 271.1% (CHI), 41.1% (PAL), 148.3% (POD), and 74.4% (PPO) in B. cinerea-inoculated blueberries, respectively. But, the activity of PPO was decreased by 55.2 and 31.9% in 500ÎŒlLâ1 ethanol-treated blueberries inoculated with A. alternata and B. cinerea, respectively, after 8days of storage. Moreover, the surface structure and ultrastructure of 500ÎŒlLâ1 ethanol-treated blueberry fruit cells were more integrated than those of other treatments. The findings of the present study suggest that ethanol could be used as an activator of defense responses in blueberry against Alternaria and Botrytis rots, by activating DREs, having practical application value in the preservation of postharvest fruit and vegetables.