Abstract: Breeding and cultivation high quality legume forage is significant for the development of livestock industry on alpine grassland.‘Algonguin’is a kind of Medicago sativa L. which has a strong cold resistance in the region, the research on hay yield and nutrient dynamic change is beneficial for the production and utilization of high quality forage. The field trial was conducted in Xiahe which located on alpine grassland， to investigate the feeding value of algonguin at different growth stages. Sampling was performed at branching, squaring, 20% bloom and 80% bloom stages, to measure forage yield, and contents of crude protein (CP), crude fat (CF), water soluble carbohydrate (WSC), ash (ASH), and mineral elements. The results showed that, hay yield was increasing with the growth of algonguin, contents of CP and CF were both higher at early growth stages, but the contents decreased at late growth stages. The content of WSC decreased firstly and increased then. The variations of ASH and mineral elements showed different variation patterns among different growth stages. The variation of ASH was in‘N’varying pattern. The variation of P, K and Na contents was in linear type, the variation of Ca, Mg and Mn was in right parabola type, while the variation of Cu and Zn was in antiparabola type. In the view of forage utilization, CP contents of forages reached the first class standard of forage grass in America, the contents of easy digestive nutrition were in medium level, the content of P, K, Na, Ca, Mg, Mn and Zn could satisfy the basic needs of livestock on alpine grassland. In conclusion,‘algonguin’was suitable for legume forage cultivation in Xiahe region, and the optimal cutting time was 80% bloom stage.