The present study was to investigate the effect of the MeJA treatment on grapes fallen from the stems during the storage at 1 ℃ and its mechanism.The results showed that the 10 μmol·L~-1 MeJA treatment could significantly reduced the fallen rate and decay incidence during the storage,and delayed the increase of ABA content,ethylene release and ABA/GA ratio,and inhibited the decrease in PME activity and increased in PG activity.Meanwhile,the MeJA-treated bunch exhibited significantly higher AIR and Na_2CO_3-soluble pectin contents compared with the controls.The water-and CDTA-soluble pectin contents in the MeJA-treated zone were lower than the controls.Therefore,these results suggested that MeJA treatment significant reduced the fallen rate in harvested grapes and improved fruit quality.The mechanism may be by the regulation of endogenous hormone level and the balance of the activities of cell wall hydrolases PME and PG,which inhibited the hydrolysis in cell wall and maintained the complete cell wall structure.