Walk behind mower with the following characteristics: deep drawing stamping steel cutting disk; adjustable rigid link arm; no tool can replace the row of mowing grass bag and crush-type plug; mower two-line approach; hand push and self-propelled (precursor or rear-wheel drive); mowing height adjustable 6-9 files, with four individually adjustable, and the horizontal bar adjustment means; mower engine is a single-cylinder four-stroke engine cold.