Mango (Mangifera indica L.) is an important tropical fruit in Hainan province. Ethylene plays a vital role in the ripening process of mango. ERF transcription factors are key downstream components of the ethylene signaling pathway, and as one of the largest families of transcription factors, they play a role in regulating signal transduction and physiological responses. To investigate the impact of ERF transcription factors on the coloration of postharvest mango peels, this study focused on the Guifei mango as the research subject. Through PCR cloning, the MiERF3 gene was obtained, and bioinformatics methods were used to analyze its basic physicochemical characteristics, conserved domains, protein structure, and evolutionary relationships. Real-time quantitative PCR (qRT-PCR) technology was then employed to analyze the specific expression of the MiERF3 gene in different tissues of mango and during postharvest storage periods. The results indicated that MiERF3 was 717 bp in length, encoding 238 amino acids. The protein had a molecular formula of C₁₁₃₀H₁₇₆₃N₃₃₉O₃₅₅S₉, a molecular weight of 26.066 kDa, and a theoretical isoelectric point of 8.62, with 30 positively charged residues and 27 negatively charged residues. The protein exhibited hydrophilic properties and a structurally unstable nature. MiERF3 protein had no a signal peptide and transmembrane region, with threonine being the primary site for phosphorylation modification. It contained an AP2 conserved domain, and its secondary structure was primarily composed of 61.67% random curl, along with 27.75% α-helix, 3.96% β-fold, and 6.61% extended chain. The three-dimensional structural model of MiERF3 contained three β-fold and one α-helix, consistent with the characteristics of the AP2 structural domain. Multi-sequence alignment and motif analysis suggested that MiERF3 belonged to the ERF subfamily. Based on phylogenetic analysis, the protein most closely related to MiERF3 was PvERF3-like from Pistacia vera, a plant belonging to the same family as mango. Onion subcellular localization and transcriptional self-activation assays showed that MiERF3 was localized in the nucleus and had transcriptional self-activating activity. Quantitative real-time fluorescence analysis showed that the expression of MiERF3 varied among different mango tissues, with the highest expression observed in the sunny side peel of mango fruit. During storage, the expression of MiERF3 showed a clear trend of initial increase followed by decrease, suspecting that MiERF3 may play a positive regulatory role in the process of fruit ripening and color change. This study would provide a theoretical basis for revealing the regulatory role of ERF transcription factors in postharvest ripening and senescence of mango.