This is a preliminary report about the GH-1 Electrode Photosyntometer designed according to Zellers principle by the Research Group of Woody Plant Introduction of Nanjing Botanical Garden. This instrument consists of a precision pH-meter, an U-shape electrode trough for absorbing CO2, an air-flow adjusting device and an asr similation chamber (leaf chamber). It is more effective and efficient, much less ex: pensive and easier to handle as compared with the QGD-07 model of infrared CO2 analyzer.