Through computer simulation, effects of edge curvature radius of blade on the mechanical properties during alfalfa cutting process were inspected. Metalloceramics functionally gradient material was fabricated by combustion synthesis casting under an ultragravity field. The structure of metalloceramics blades was prepared as national standard. Formation principle of selfsharpening characteristics and lowdamaged mechanism cutting alfalfa for the metalloceramics blades were analyzed. Research results were verified by field experiment. The results indicated that edge curvature radius of blade was the key factor influencing the sharpness property. More value of radius was, blunter of the edge would be. According to stalk of alfalfa cut by blades, reducing cutting and increasing striking aspects would be existed. In the alfalfa growth direction (Z direction), enhanced tensile stress can accumulate the stalk, which can lead to some disadvantage such as coarse stubble of stalk, root loosen and so on. The flank surface of blades were made up of metalloceramics with preferentially oriented columnar eutectic matrix of iron/iron carbides for the high hardness (760~780Hv) and wear resistance. Hardness gradient variation of rake face of blades can lead to regular wear. Selfsharpening characteristics, sharp cutting performance and lowdamaged cutting alfalfa for metalloceramics blades were so formed because of slight variation for their edge structure. The results of field experiment indicated that in the same condition, after harvesting alfalfa plant for 66.7hm2, compared with the commercial blades, the designed blades had excellent cutting performance: flush notches, slight damage of tissue, natural selfhealing process, shorten regeneration period for 5 to 10 days and so on.