For the deficiency of productive alfalfa varieties which can adapt to the cold regions, some original materials were loaded in Shijian 8 breeding satellite and transported into space to select and breed a new high-yield and cold-resistant alfalfa variety in 2006. Two new strains were bred based space mutation breeding. Ecological adaptability, growth period, fresh and dry forage yield, leaf/stem, plant height of all the strains（varieties）. Seed yield and nutrition composition were measured by the strains（varieties） comparison experiment from 2017 to 2020. The result showed that Synthetical Strain 1 is cold resistant and high yield, with an average annual hay yield of 17,038 kg/ha and seed yield of 312 kg/ha, which is in line with breeding objectives.