Objective: To investigate the cross-modal enhancement effect of 30 key ester compounds in beverage alcohol on taste perception using a 40% ethanol aqueous solution as the medium， and to reveal the structure-activity relationship between this effect and molecular structure， physicochemical properties， and binding energy with olfactory receptors. Methods: Using a 40% ethanol aqueous solution as the matrix， the taste thresholds of 30 ester compounds were determined under both olfactory blocked and normal perception conditions by the ten-cup method， and the cross-modal taste enhancement multiple was calculated. Molecular docking technology was used to calculate the binding energy of each ester with the olfactory receptor OR51E2. Further， the carbon chain length， LogP， Henry's constant and other physicochemical parameters were correlated， and the key influencing factors were revealed through Spearman correlation analysis. Results: The taste enhancement multiple of the 30 ester compounds ranged from 1.0 to 8.5. Among them， the straight-chain saturated C6-C10 ethyl esters (such as ethyl caproate and ethyl octanoate) had the highest enhancement multiple， significantly higher than those of aromatic esters and lactic acid esters (P < 0.05). The introduction of branched structures and hydroxyl groups significantly weakened this enhancement effect (P < 0.05). The enhancement multiple was significantly negatively correlated with the binding energy of OR51E2 (r = -0.663， P < 0.0001) and Henry's constant (r = -0.700， P < 0.0001). Conclusion: The straight-chain saturated C6-C10 structure was the advantageous skeleton for ester compounds to exert cross-modal taste enhancement effects， and carbon chain length， volatility and olfactory receptor affinity were the core driving factors of this effect. This study revealed the structural basis of ester compounds enhancing taste perception through the olfactory pathway at the molecular level， providing quantitative basis and theoretical guidance for the flavor design and cross-modal flavor regulation of beverage alcohol.