Abstract: Chemical constituents in leaf of pinus tabulaeformis Carr. at different seasons were analyzed. The volatile components in leaf of pinus tabulaeformis Carr. were extracted by steam-distillation, separated by gas chromatography and identified by gas chromatography-massspectrometry(GC/MS). The results show that the extraction rate and composition of the volatile oil are notably varied at different seasons. The major components of the volatile oil in leaf of pinus tabulaeformis Carr. are α-pinene,β-pinene, limonene, bornyl acetate, caryophyllene and camphene. The relative contents of each component at different seasons are different.