An improved grass-discharging-passage stirring and cutting mechanism for a rear shaft at a bottom of a lawn mower is disclosed. A grass-discharging-passage stirring and cutting mechanism for a rear shaft of a lawn mower, wherein the lawn mower comprises a gear (j2) and a stirring and cutting rod (j1) arranged on the noise-elimination inner shaft (j1a) of the rear shaft of the lawn mower, wherein the noise-elimination inner shaft (j1a) is hollow； the rear shaft of the lawn mower has a shape of a hollow tube； the rear shaft of the lawn mower is divided into a left (z1) and a right shaft (z2), and the noise-elimination inner shaft (j1a) is arranged between the left and the right shaft； the noise-elimination inner shaft (j1a) is divided into 3 sections； the middle section has a same diameter as the rear shaft of the lawn mower, and the left section and the right section are hollow tubes which have internal diameters smaller than those of the left and the right shaft； the left section of the noise-elimination inner shaft (j1a) is inserted into the left shaft, and the right section is inserted into the right shaft of the rear shaft of the lawn mower.
