Chlorophyll Meter can measure the relative chlorophyll content (unit SPAD) or green degree, nitrogen content, leaf moisture, leaf temperature of the plant in real time, so as to understand the true nitro requirements of the plant and understand the degree of soil nitro deficiency or whether too much nitrogen fertilizer is applied. This instrument can increase the utilization rate of nitrogen fertilizer and protect the environment. It can be widely applied to the research of plant physiological indexes and the guidance of agricultural production in agriculture and forestry related research institutes and universities.