Abstract: This study researched four grasses: Hordeum brevisubulatum, Roegneria turczaninovii, Bromus inermis and Elymus nutans. The study was conducted in 2006-2007 in Inner Mongolia at the Linxi seed field; it assessed the development the different growth stages of plant nutrients and analyzed plant stems and leaves of nutrients as well as their amino acid values (amino acid ratio coefficient). The results were as follows: over the entire growth period, the crude fiber content in all four types of grass changed the magnitude of coarse protein as the grass grew and its content was gradually increased. Crude ash and crude fat content barely changed during the entire growth period. The study analyzed the nutrition of the four grasses. The results showed that Hordeum brevisubulatum contained moderate levels of calcium and high phosphorus. Roegneria turczaninovii, Elymus nutans and Bromus inermis all contained low levels of calcium and moderate phosphorus. The ratios of calcium and phosphorus of Hordeum brievisubulatum and Roegneria turczaninovii were in the perfect range but those of Elymus nutans and Bromus inermis were not. EAAI values of the four grasses were higher than 0.95 indicating that the grasses were well-fed.