The work aims to improve the properties of wear resistance and cutting sharpness of rotary mower cutter, so as to realize the long service life of blades and lower the damage to crops. The flank surface and tip point of blades were heat-treated by carbon-nitron-boronized with rare elements catalysis technique. Scanning electron microscope (SEM), optical microscope (OM) and microhardness tester were used to detect the microstructure, components and hardness distribution of co-infiltrated layer. The self-sharpening characteristic formation mechanism of blades in the operation process was studied and verified with field test. After treatment of carbon-nitron-boronized with rare elements catalysis (850 ℃×4 h), the flank surface and tip point of blades were composed of boride layer (about 50~70 μm thickness) and carbonitriding layer (about 750~1000 μm thickness). The cutting edge hardness of boride increased due to hypereutectic treatment after high frequency induction quenching in oil. Therefore, gentle gradient variation of microstructure, components and hardness of heated blades was exhibited following the thickness direction and the support ability of carbonitriding layer to external boride layer remarkably increased. In the working process, the blades had longer serve life due to higher hardness flank surface and cutting edge, excellent wear resistance as well as difficult peeling and edge flaking. The protruding cutting edge could always keep sharp cutting performance, thus forming self-sharpening characteristics and realizing low-damage cutting of regenerated crops. The results of field test indicated that compared with the blades available in the market, the co-infiltrated blades had higher wear resistance and could still keep the sharp cutting performance after long-term operation, which was conductive to the healing and regeneration of crop cutting damage. The blades after treatment with carbon-nitron-boronized with rare elements catalysis technique can form the self-sharpening characteristic in the operation process because of uniform gradient microstructure, components and hardness distribution for the flank surface and tip point, thus realizing the long service life and lowering damage to crops.