In order to study the effects of aging time, cooking degree and their interaction on beef flavor components, the longissimus dorsi of Simmental cattle in the process of aging time (3, 5, 7 d) were selected to make steaks of medium, medium well and well done. Volatile flavor components in different aging times and cooking degree were analyzed by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), explored the best aging time and cooking degree which were beneficial to flavor substances formated. Results showed that, a total of 50 volatile compounds were identified in each beef sample. The relative content of ester compounds was positively correlated with aging time, negatively correlated with cooking degree. The relative contents of hydrocarbons, ketones were negatively correlated with aging time and cooking degree respectively. However, the relative content of aldehydes was positively correlated with aging time and cooking degree. Furan compounds were only detected in beef with aging for 7 days. Principal component analysis (PCA) and comprehensive factor scores showed that the medium well beef with aging for 7 days gained the highest comprehensive score, which was the most conducive condition to form better volatile flavors in beef.