Abstract: Cinnamomum longepaniculatum is an economically significant tree species whose essential oil has garnered considerable attention due to its biological activities, including antibacterial and antioxidant effects. As the stem constitutes a major part of the tree, studying the content and composition of its essential oil can help expand future utilization approaches for C. longepaniculatum plantations. In this study, steam distillation was used to extract essential oil from the stems, and gas chromatography-mass spectrometry (GC-MS) was employed to analyze its chemical constituents. The influence of different stem segments (upper, middle, and lower) and tree age (10, 20, 30, and 40 years) on oil content and composition was investigated. The results showed no significant difference in oil content among stem parts. The average oil content ranges for the upper, middle, and lower segments across tree ages were 0.72%～0.93%, 0.90%～0.97%, 0.85%～1.25%, and 2.67%～3.04% for 10, 20, 30, and 40-year-old trees, respectively. However, the average oil content (exemplified by the middle part) increased significantly with tree age: 0.72% (10 years), 0.96% (20 years), 1.25% (30 years), and 2.73% (40 years). GC-MS analysis revealed that the main components of the stem essential oil were 1,8-cineole, α-terpineol, 4-terpineol, and safrole. The relative content of 1,8-cineole was highest (53.83%) in the middle part of 10-year-old trees. In contrast, α-terpineol content showed no significant variation among parts or ages, ranging from 13.77% to 16.56%. The content of 4-terpineol showed little variation among parts (8.66%～10.41%) but decreased with increasing tree age (from 10.41% to 3.88%). Conversely, the relative content of safrole increased markedly with tree age, from 6.91% to 25.36%.