Abstract: 【Objective】 To clarify the effect of hydroponic culture on the amino acid composition of whole plant barley (Hordeum vulgare L.) and wheat (Triticum aestivum) seedlings, and compare the difference of their nutritional value, so as to provide a basis for the development and utilization of hydroponic green fodder and crop screening. 【Methods】 Taking common barley (Ganpi 8) and wheat (Xindong 18) varieties in Xinjiang as the research object, after 3 days of germination and 5 days of hydroponics treatment in a controlled environment, the amino acid content of the stem and root parts of the whole plant of hydroponics barley and wheat were determined respectively. At the same time, the amino acid composition and nutritional value of barley and wheat seeds without germination and hydroponics were analyzed as the control. 【Results】 The results showed that compared with the seed, after 5 days of hydroponic culture, the total amino acid content of barley and wheat in the stem and leaf increased by 129% and 102%. The content of other 16 amino acids increased significantly (P<0.05), otherwise the glutamic acid content decreased. The content of lysine increased 3-4 times, and the contents of delicious, sweet, aromatic and effective amino acids increased also; The contents of essential amino acids, total amino acids and special functional amino acids in wheat roots decreased slightly, the content of nonessential amino acids in barley roots decreased by 10%, and the contents of sweet and effective amino acids increased slightly. Compared with the two crops after hydroponics, the contents of 12 kinds of amino acids in the stems and leaves of wheat were the highest(P<0.05), such as lysine, aspartic acid and alanine. The contents of flavor amino acids and effective amino acids were significantly higher than those of barley; The contents of leucine, proline and other five amino acids in barley stem and leaf were the highest (P<0.05). 【Conclusion】 To sum up, after 5 days of hydroponic cultivation, the seeds and seedlings have enriched the amino acid nutrition of the stems and leaves, and the amino acid nutrition value of hydroponic wheat is higher than that of barley.