Through measured the indexes related to growth, yield and quality of Gannong No.3, Gannong No.5 , tourists alfalfa and their hybrid offspring, using gray relevancy analysis method of the gray systematic theory, structured the comprehensive evaluation model for all materials , selected fast-growing 12 # and fast-growing 11 # of the hybrid offspring as the best strains, including growth height were 105.44 cm, 105.42 cm; Growth rate were 1.74 cm/d, 1.68 cm/d; stem-leaf ratio were 0.30 and 0.35; Branch number were 23, 17; fresh yield were 39.99 t/hm2, 35.13 t/hm2; Crude protein content were 19.95% and 23.89%, Relative feeding value for 153.15%, 157.02%. Relatively good strains were Many leaf 2 #, fast-growing # 5, fast-growing 20 #, fast-growing 21 #.