The invention discloses a decayed garbage crushing machine. The decayed garbage crushing machine comprises a base (1), a shell (2), a feeding hopper (3) and a discharging opening (4), wherein the shell (2) is fixed to the base (1); the feeding hopper (3) is arranged at the top of the shell (2); and the discharging opening (4) is formed in the bottom of the shell (2). A longitudinal main shaft (6) is mounted on the shell (2) through a bearing (5). One end of the main shaft (6) is connected with a transmission device arranged outside the shell (2). A crushing mechanism is further arranged on the main shaft (6). The crushing mechanism comprises multiple hammer slice locating plates (7) which are uniformly arranged in the axial direction of the main shaft (6). All the hammer slice locating plates (7) are connected through four pin shafts (8). Each pin shaft (8) between the corresponding two adjacent hammer slice locating plates (7) is provided with a hammer slice (9). By means of the decayed garbage crushing machine, decayed garbage can be well crushed, and the decayed garbage can be prevented from blocking the crushing machine; and furthermore, energy consumption of the crushing machine can be greatly lowered, and thus manufacturing cost of equipment is saved.