[Aim]  Aphis gossypii is a serious pest of the Chinese wolfberry, cotton and other crops. The aim of this study was to identify the binding characteristics of odorant-binding proteins with odor molecules and establish their role in the olfactory recognition process in A. gossypii. The findings will establish a theoretical basis for using chemical volatiles in developing lures aimed at the future prevention and control of A. gossypii. [Methods]  Using transcriptome data, a full-length sequence of the odorant-binding proteins (OBPs) AgosOBP5 gene was obtained and bioinformatics analysis was performed. The prokaryotic expression of AgosOBP5 was constructed and detected by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). Fluorescence competitive binding experiment was used to study the binding characteristics of the AgosOBP5 recombinant protein with six different odor molecules derived from plants. [Results]   The total length of the A. gossypii gene AgosOBP5 was 675 bp, encoding 224 amino acids, including 12 conserved cysteines. The predicted theoretical relative molecular weight was 54.50 kD. Sequence alignment and phylogenetic tree analysis show that the amino acid sequence of AgosOBP5 in A. gossypii has the highest homology with the AglyOBP5 in soybean aphid A. glycines. By Isopropyl β-D-thiogalactoside (IPTG) induction and SDS-PAGE detection, it demonstrates that the recombinant protein AgosOBP5 is soluble and can be expressed in the supernatant. The test results show that these six odor molecules can reduce the fluorescence intensity value of the AgosOBP5 and N-phenyl-1-naphthylamine (1-NPN) fluorescent probe system to less than 50%. Starting from the initial dropwise addition of the five compounds including methyl salicylate, 2-phenylethanol, benzyl alcohol, nonanal, and 1-octen-3-ol, the fluorescence value began to decrease and continued to maintain a downward trend. However, palmitic acid initially showed an increasing trend at the concentrations below 96 μmol·L^-1, this trend reversed later and showed a continuous decrease at other higher concentrations. [Conclusion]  This study identified the nucleotide and amino acid sequences of protein encoded by AgosOBP5 in A. gossypii. The protein AgosOBP5 has a higher binding affinity with methyl salicylate, 2-phenylethanol, benzyl alcohol, nonanal, and 1-octen-3-ol the five kinds of green leaf volatiles. It is inferred that AgosOBP5 protein may play an important role in the ordor information recognition of A. gossypii.