The object of this study was to analyze changes in peroxidase activity in needles of Pinus sylvestris during a year. We collected first, second, third years needles. The activity of guaiacol dependence peroxidase was determined. The minimum peroxidase activity was showed in January-February. Increasing of peroxidase activity in needles of all years in March accompanied with intensification physiological processes and activation of metabolism in plant in spring. There are more or less high level guaiacol peroxidase activities from September to November due to contribution of it at stress-adaptation to low temperature in winter period. Peroxidase activities are change during a year due. There are own level peroxidase activity for needles different generation years at different time period.