Abstract: Marinated beef is highly favored by consumers for its distinctive flavor, with marination serving as a critical pre-treatment step that decisively influences the final product quality. In this study, lemon juice and beer were used as marinades. An electronic nose (EN) was employed to differentiate the overall flavor profiles of beef marinated with different agents over various storage periods (0~4 months). Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was applied to qualitatively and quantitatively analyze the volatile flavor compounds in marinated beef. Cluster analysis and correlation analysis were further conducted to explore the relationships among marinade type, storage time, and key flavor components. The results indicated that marination with lemon/beer could significantly improve the flavor of marinated beef, and the overall flavor characteristics changed during storage. A total of 17 key compounds with odor activity values (OAV) greater than 1 were identified in marinated beef, namely linalool, phenylethyl alcohol, α-terpineol, pentanal, hexanal, heptanal, octanal, nonanal, lauric aldehyde, isoamyl acetate, β-pinene, D-limonene, γ-terpinene, 4-ethyl guaiacol, eugenol, anethole, and estragole. Marinades showed significant correlations with most key flavor compounds: lemon marinade increased the OAVs of terpenes and lauric aldehyde, whereas beer marinade significantly reduced the OAVs of short-chain straight aldehydes (P<0.05). Storage time was negatively correlated with the OAVs of phenolic, ether, and terpene key flavor substances and strongly positively correlated with the OAV of nonanal. Marinated beef marinated with a lemon-beer combination had rich mint notes from D-limonene and floral aromas from linalool, while the fatty aroma contributed by short-chain straight aldehydes was significantly reduced (P<0.05). The overall flavor was fresh, and flavor changes were relatively slow during storage. These findings provide theoretical and technical references for clarifying flavor changes during the storage of marinated meat and optimizing the marinade formulation for marinated beef.