Abstract: Five sites were sampled to analyze the biomass and nutritive value of Potamogeton crispus at the stages of greening, exponential growth, bud emergence and decline. In the exponential growth phase, biomass increased: the contents of crude protein, crude fat, total P and β-carotene were the largest. From March to June, the contents of crude fiber, crude ash, calcium and Vc showed a gradually rising trend. May was the best time for harvesting P. crispus. The nutritive value contents of P. crispus were different at different sampling sites but over the whole growth period of P. crispus at all sampling sites, the contents of crude protein were more than 100 g/kg while those of crude fiber were less than 155 g/kg. The contents of crude fat were more than 12 g/kg and of crude ash were more than 140 g/kg. Ca and total P contents were more than 3.0 g/kg while those of Vc were more than 140 mg/kg, and the contents of β-carotene more than 310 mg/kg. The nutritive values of P. crispus were more than that of other hydrophytic feeds and it was the best feed for fish and domestic animals. The carotene contents of P. crispus could improve health value of eggs and the prospects for applications of P. crispus are very wide.