Abstract:The lake Liuhai is consisted of 6 small lakes located in central urban area of Beijing city (Fig.1)The investigation of algal community related to the trophic level in lake Liuhai was carried out monthly through Jan.to Dec.1987 The results obtained on the first 4 lakes are as follows.1. The algal species, density and diversity index in the lakes appeared obvious horizontal variations, and the number and diversity index of species in lake Shishahai, i. e., Lakes Xihai, Houhai and Qianhai, were remakbly highe...