The plant photosynthesis meter is an experimental instrument for testing the photosynthesis of living leaves of plants in artificial climate chambers, greenhouses, greenhouses, fields, etc. The measurement content includes ambient temperature and humidity, leaf room temperature humidity, air CO2 concentration, photosynthetically active radiation intensity, There are 12 parameters in total including leaf surface temperature, leaf net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO4 concentration, and instantaneous water use efficiency. They can be used for scientific research on plant growth physiology, photosynthetic physiology, stress physiology, etc., and are suitable for agricultural research. , teaching, horticulture, grass farming, forestry and wider areas.