The paper represents the results of a successive study on the succession of algal community and the changes of algae number as well as the limiting nutrient for algae growth in Taipinghu Reservoir during 1992~1993. As comparied with the previous data(1985~1986) by the author, it is decreased in the species diversity of algae with more than 30% reduced in the total species number, and the species of micro algae is increased notably. The mean wet weight per algae cell is reduced by 63.6% in pelagic zone and 75.4 in bay area after an interval of about 7 years. However, the mean annual cell densities in pelagic zone and bay area are increased by 3.6 and 5.6 times respectively. According to the results of nutrient spikes, it is possible that phosphorus is still a limiting factor to aJgae growth. The AGP of the reservoir is only equal to 25% of the HB T-5 control medium.