A three-wheeled lawn mower having two rear grass discharge openings. The two rear grass discharge openings (33) are provided respectively on a left and right side of a channel extending from a grass cutter to a grass collection bag of a grass collection container, so as to allow grass from a left grass cutter and a right grass cutter to pass through, thus solving a grass jamming problem. The two rear grass discharge openings (33) have a rectangular or inverted trapezoidal shape, and are respectively provided with a cover torsion spring and adjustment positions to facilitate adjustment. The lawn mower has a front-wheel drive applicable for a steep slope, and four meshing grass cutting disk gears (34) applicable for cutting tough grass. In addition, the three wheels enable more flexible turning than four wheels, thus providing applicability in various sites.
