The chlorophyll (blue-green algae) water quality analyzer uses the characteristic that chlorophyll (blue-green algae) has absorption peaks and emission peaks in the spectrum, and emits monochromatic light in the spectrum absorption peak of chlorophyll (blue-green algae) to irradiate the water , The chlorophyll (blue-green algae) in the water absorbs the energy of monochromatic light, and releases a monochromatic light with another wavelength emission peak. The light intensity emitted by chlorophyll (blue-green algae) is proportional to the content of chlorophyll (blue-green algae) in the water. Proportional.