In this study, role of total proteins, peroxidases and polyphenoloxidases in metabolismes of juniper were studied. For this purpose, seasonal alteration (quantitative and qualitative) of total proteins, peroxidases and polyphenoloxidases from branches, leaves, male cone and bery were analysed by electrophoresis and spectrophotometric methods in male, female and male-female plants. Results indicated that in spite of specific differences in each stand, activity pattern of enzymes were similar. The highest activity of peroxidases from leaves and branches were seen in spring and autumn and the lowest activity were in summer and winter. Protein, peroxidases and polyphenoloxidases rates of male cone decreased in winter. Comparision of peroxidases with polyphenoloxidases activity during female maturity indicated that maximum activity of polyphenoloxidase was in the first stage growth and minimum activity of peroxidase was in second stage growth.These results indicated this enzyme involves in juniper metabolisms such as, growth and development, photosynthesis, hormonal balance, organogenesis, morphogenesis and resistance to environmental conditions.