Abstract: Objective:To determine the main nutrients of hellgrammites and to investigate its antidiuretic effect. Methods:The contents of hellgrammites soluble protein, polysaccharide, oil, water and organic acid were determined by Coomassie blue method, Phenol-sulfuric acid method, Soxhlet extraction method, Direct drying method and Titration method, and the amino acid composition was determined by amino acid analysis. At the same time, the rats model of water load were used to investigate the antidiuretic effect of hellgrammites. Results:The contents of soluble protein, polysaccharide, oil, water and organic acid in hellgrammites were 4.87%±0.03%, 1.90%±0.09%, 16.45%±0.70%, 71.51%±0.66%, 3.54%±0.06%, respectively. A total of 14 kinds of amino acids were detected, and the total amino acid (TAA) content was 52.01 g/100 g. The ratio of essential amino acids to total amino acids (EAA/TAA) was 48.18%, and the ratio of essential amino acids to non-essential amino acids (EAA/NEAA) was 92.99%. The anti-diuretic experiment showed that hellgrammites could significantly reduce the amount of urine and could significantly increase the serum vasopressin content (AVP) in rats. Conclusions:The protein and polysaccharide contents in hellgrammites are rich, the amino acid composition ratio is in line with the high quality protein standard, and it has obvious anti-diuretic effect, so that hellgrammites has good edible value and medicinal development potential.