Abstract: In order to explore the effect of exogenous CO on proteome of postharvest jujube infected by Aternaria alternata,the protein expression level during the invasion of A.alternata was determined by using isobaric tag for relative and absolute quantification proteomic analysis methods in this experiment,and the differentially expressed proteins were identified,GO(gene oncology)and KEGG(kyoto encyclopedia of genes and genomes)pathway of them were analyzed. The results indicated that a total of 2158 proteins were identified,of which the total number of differentially expressed proteins was 1053,of which the number of up-regulated differentially expressed proteins was 443 and the number of down-regulated differentially expressed proteins was 610.GO enrichment analysis revealed that the differential proteins were mainly located in the cytosol,cytoplasm,cell membrane and organelles. Protein binding,abscisic acid binding,isoprenoid binding,hormone binding,ethanol binding,phosphatase inhibitor activity and monocarboxylic acid binding were the seven main molecular functions of differential proteins. Single-organism metabolic process,single-organism cellular process and single-organism process were the three shared biological processes of differential proteins.GO and KEGG pathway enrichment analysis showed that the differential proteins were mainly enriched in five main functions and processes,carbohydrate and energy metabolism,amino acid and lipid metabolism,biosynthesis of secondary metabolites and defense-related proteins,signal perception and signal transduction,transcription and post-transcriptional regulation,respectively. The above results provide theoretical support for further exploring the mechanism of CO in the protection of jujube fruit against postharvest pathogen invasion.