Abstract: Zizania latifolia is one of the major aquatic macrophytes in lake Honghu, Hubei province. It covers an area of 127 Km2 in the lake(355 Km2), with a biomass of the shoot of 4379g m-2 in fresh wt. and a potential annual yield over 121,700 tons dry wt in total. However, it has not yet been used effectively.Protein and amino acids in different organs of this plant were analyzed. In terms of percentage in dry wt, the contents of protein and amino acids are 7.0 and 4.76 in root, 11.3 and 8.85 in rhizome, 9.5 and 7.15 in stalk, 22.4 and 16.53 in tender stalk, 16.8 and 14.61 in leaf, respectively. It was found that the contents of the essential amino acids in 500 g dry wt of leaf approximate to that of the essential amino acids in 100 g dry wt of dorsal muscle of the juvenile grass carp.Other chemical constituents were also determined. The contents in percentage are: fat, 3.4-4.2 in leaf and 2.2 in stalk; crude fiber, 26.8-28.0 in leaf and 24.2 in stalk; ash, 10.0-10.3 in leaf and 5.8 in stalk. The stalk contains soluble carbohydrates more than 30% of dry wt and glucose, fructose, sucrose and maltose are rich, Thus, Zizania latifolia is a feeding crop of high quality.