Abstract: The mechanism of cold tolerance of Hami melon fruit induced by OA treatment was studied. ‘Xizhoumi No. 25’ Hami melon fruit was used as the material,the control group were socked in clear water and the treatment group was soaked in 15 mmol/L OA solution for 10 min respectively. The variation of the electrolyte leakage and the MDA concentration were measured,and transcriptome sequencing was conducted on the pericarp of Hami melon fruit on the day of harvest(Yuanshidian:YSD),and from OA treated(T)and untreated(C)fruit after storage at 3℃ for 42 days. The results showed that OA treatment decreased the electrolyte leakage and the MDA concentration,and relieved the occurrence of chilling injury after harvest. A total of 418943882 clean reads were obtained,which were spliced and 252169 contig fragments were obtained,and 153128 unigene fragments were further assembled,71.28% percent of unigenes were annotated in NR database and of which 56% unigenes matched to the published melon genome sequence. 33346(21.8%)unigenes in KEGG were successful annotation,the number of genes in the metabolic pathway was greater. The regulations of cold stress by OA treatment in Hami melon fruit during cold storage were mainly concentrated in the carbohydrate metabolism pathway.