A composite rotary tillage lawn mower relates to the field of agricultural and forestry machinery technology, including an installation disc, a lawn mower, and a loosening blade. The lawn mower and loosening blade are alternately arranged at intervals around the installation disc; One side of the rotation direction of the loosening blade is equipped with a loosening blade, and the bottom end of the loosening blade is equipped with several cutting teeth; One side of the rotation direction of the lawn mower is equipped with a lawn mower blade; There are installation holes on the installation disk.