Abstract: Experimental results in relation to the effects of water temperature, light intensity, pH and population density on productivity of Potamogeton crispus, with the estimations of the productivity and the chlorophyll content in different parts of this species are reported here in.Under light intensity of 8000 lx and water temperature of 22—28℃, the gross production of the apical portion of Potamogeton crispus varies from 0.08 to 1.06 mgO2·h/0.5 g fresh weight, with an average of 0.92 mgO2·h/0.5 g; net production ranges 0.44—0.79 mgO2·h/0.5 g, 0.61 mgO2·h/0.5 g in average. The mean photosynthetic rate is 1.11% and the mean respiration rate is 0.53% per hour.