Abstract: Essential oil was extracted by hydro-distillation method from pine needles in different seasons with different storage time and then GC-MS analysis was carried out to determine chemical composition of the essential oil. The yield of pine-needle essential oil gathered in June was 0.61% and the major components of essential oil had the following order; α-pinene(19.00%), sabinene(19.61%), elemol(15.38%), bornyl acetate(10.05%). Total amount of terpenes in the sample of June exceeded 88.40%, which was the highest among the tested. After storages of 1, 3, 6, 12 months, oil yields of dry sample were 0.60%, 0.58%, 0.53% and 0.21%, respectively, while the amounts of terpenes in the essential oil were 79.93%, 76.03%, 74.33% and 64.97%, respectively. With the prolonging of storage time, the concentration of monoterpene in essential oil decreased, whereas the concentration of oxygenated terpene increased.

Key words: pine needles, essential oil, storage time