Abstract: A field experiment was conducted to compare the comprehensive benefit of alfalfa with that of corn in Tongliao in Inner Mongolia.The results show that the dry matter yield of alfalfa is only 48.8% of that of corn，while the crude protein yield of alfalfa is higher than that of corn with 66.3%. Although the input and output values of alfalfa are both lower than those of corn，the net output values of them are nearly equivalent.The dry root weight of alfalfa is 3.06 times of that of corn，bulk density and porosity of alfalfa field are 95.53% and 104.81% of those of corn field respectively in 0～30cm soil layer.The organic matter，alkaline hydrolysis N，available P and pH of alfalfa field are all lower than those of corn field，while available K is higher than corn field in 0～20cm soil layer.The deflation of alfalfa field is only 41.81% of that of corn field in spring.