Abstract: Based on growing alfalta in the third year in field of sah-aftected land in Hetao, orthogonal experiment was set totest the influence of production and quality- by using different tertilization combinations of nitrogen, phosphorus and potassium.The results showed that fertilization significantly increased the production of altalfa and P was better than K and less N wasbetter than more N ;alfalta production reached maximum value of 8 428 kg/hm2 while the combination was N2P6K4, which was48.4% higher than the control group.Altalth highest economic benefits was 196.2 yuan/667m2 and income rate reached 38.2%while the combination was NOP2K2. Fertilization combination of N-P, N-K and P-K can significantly increase the contents ofcrude protein and crude tat, but with the increasing of tertilizing amount, the growth trend showed a tendency of decreasing.