Achillea genus is belonging to Asteraceae. The composition of the active ingredients of plants in different climatic conditions show very different constituent in phytochemical propertiesand , In order to investigating quantity and quality of essential oils of three species of achillea in Zanjan provences plant samples collected from northern heights of Zanjan After selecting a suitable plants, after harvesting the whole vegetative body of the plant was harvested in the full bloom time and after drying in room, and its essential oil was extracted by distillation . Then, the components of the essential oil were identified and the amount of the components was identified using a gas chromatography device connected to a mass spectrometer. The results showed that the essential oil of Achillea wilhelmsii C. Koch had a yellow color with a yield of 0.89%. The results of GC-MS showed that the essential oil of this plant is composed of 106 substances in which 15 representative compounds 54% were total essential oil. In the study of essential oil of Achillea tenuifolia Lam, it was found that 20 substances constituted 54.37% of essential oil. Also, the essential oil of Achillea millefolium was white with a yield of 0.74%, GC-MS results showed that this essential oil The plant in the region is composed of 105 substances, of which 10 compounds represented 50.78% of the total essential oil Which 47 compounds accounted for 81.05% of the essential oil.