An improved grass-discharging-passage stirring and cutting mechanism for a rear shaft at a bottom of a lawn mower. Ultra-thin blades are adopted since a grass-discharging passage is very narrow and small while many stirring and cutting rods and blades are used. The blade is firstly placed into mixed buried soil, is subjected to thermal treatment, is scanned by variable-frequency electromagnetic field and laser, and is subjected to electromagnetic co-penetration heat treatment under platinum-rhodium catalysis then the blade is subjected to organic post-treatment, is heated at a co-penetration turning point of 723° C., and then quenched in organic matter of horse urine a noise-elimination inner shaft of the rear shaft of the lawn mower is hollow and has a plurality of noise-elimination wedges for facilitating noise elimination and reduction. The improved mechanism may be powered directly by a three-stage planetary retarder connected to an electric motor.
