A mechanical air-assisted spraying machine comprises a power device, a medicine pump, an air tube shell and a fan blade, wherein the fan blade is arranged inside the air tube shell, the power device is connected with the fan blade and the medicine pump by a transmission device respectively, and the power device is connected with a power generating set. The mechanical air-assisted spraying machine can directly convert mechanical energy of the power device into kinetic energy of the fan blade, thus avoiding energy loss caused by repeated energy conversion and reducing energy loss. In addition, an air tube is not required for installing a motor, and the air efficiency of an air inlet of the air tube can be improved, thus the spraying distance can be increased and the spraying efficiency can be improved.