The paper presents the results regarding the phytomonitoring of physiological processes in pear trees. The modern RTM-48A phytomonitor was used, which allowed the measurement of indices in the form of a film-phytodiagram that allows the diagnosis of the properties of genotype and physiological con-dition of plants. The light saturation curve for photosynthesis in pear plants was determined as a result of the evaluation of the intensity of photosynthesis, respiration, transpiration, stomata conductivity as a func-tion of temperature, humidity and CO2 content in the air. The minimum value of light at which the photo-synthesis process is initiated has been established. As the light intensity increases (1/3 of the total light) the intensity of photosynthesis increases after the essential optimization of the process has taken place.