Abstract: In order to breed new varieties（lines） of high-yield of Alfalfa, CGA analysis and genetic parameter estimation were carried out for plant height, branch number, yield and other traits of the first generation cross combinator materials obtained from the cross between the ten superior single plants. The results showed that the single plant materials with high GCA were Warrior and Gannong No.3, which had excellent characteristic of high yield, and could be used as the parent materials to participate in the breeding of new alfalfa varieties（lines） with high yield or high yield and good quality.By analyzing the genetic parameters of annual total hay production, total plant height and average branch number of alfalfa, the general heritability arranged from big to small : total plant height, total hay production, average branch number, and the total plant height was more than 50%, which could be selected in early and middle generations.The genetic coefficient of variation arranged from big to small: total hay production, mean branch number, total plant height, and total hay production had the greatest selection potential.