Medicinal plants are one of the most important genetic resources in Iran. Yarrow belongs to Asteraceae family and it has different medicinal and ornamental uses. The aims of this study was to evaluate the effect of different phenological stages on antioxidant properties, essential oil content, plant morphology, self-compatibility index and antiglycation property in different genotypes of Achilla including A. millefolium (Hamadan, Kandovan, Lithunia, England, and Uroumiyeh), A . filipendulina (California and Ardebil), A. santolina (Shahrkord), A. nobilis (Shandiz), A.aucheri (Alborz) and A. pachycephalla (Hamadan and Golestan). In addition, the main ingredients of alcoholic extract of the mentioned genotypes were evaluated and compared by spectroscopy method. The experiment was conducted in a split plot in time based on randomized completely block design with three replications in 2014-2016. In this study antioxidant activity were evaluated based on DPPH and FTC method. Results showed that in all the genotypes the highest amount of phenol, flavonoid, FTC (in all concentrations) and antiglycation activity observed in 50% flowering stage. Furthermore, the lowest antioxidant activity (evaluated by DPPH method) was observed in this stage. In terms of morphological traits, California genotype at 100% flowering had a great advantage in comparision with other genotypes. The highest amount of essential oil in all studied genotypes was observed at 100% flowering stage. Results showed that phenolic content and antioxidant activity in the first year was higher in comparison to the second year. The highest amount of total phenolics (111.10 mg tannic acid per gram dry weight) and flavonoids (15 mg quercetin per gram dry weight) were observed at 50% flowering stage in Golestan genotype in the first year. Also, this genotype possessed the highest FTC, the lowest IC 50 , and the highest antioxidant activity in mentioned stage and year. Furthermore, the major compounds of alcoholic extract of different species were evaluated using High-performance liquid chromatography (HPLC). High amounts of fenolic and flavonoid compounds such as chlorogenic acid, luteolin and quercetin was determined in the extract of different Achillea species extracts. Among these compounds, chlorogenic acid and luteolin had the most important role of increasing in antioxidant and antiglycated activity. The highest essential oil content was obtained at 100% flowering in Lithuania genotype as 0.8% and 0.7% in the first year and the second year, respectively. During the years, Ap-hamadan and A.aucheri had the lowest (0.01%) essential oil content. So, the best harvesting time in term of phenolic compounds and antioxidant activity was 50% flowering , while for essential oil content was 100% flowering stage. In this study, there was a direct correlation between antioxidant and anti-glycation activity. Keywords : Phenological stages, Achilla , Antioxidant activity, Phenolic compounds