The invention relates to a belt-breakage-prevention monitoring device for a pig-casting machine chain belt. The belt-breakage-prevention monitoring device comprises the chain belt. A through shaft is arranged on the chain belt. The two sides of the chain belt are provided with alarm limiting switches respectively, wherein the alarm limiting switches are used for limiting the through shaft. The alarm limiting switches are connected in parallel and then connected with an alarm in series. A button switch is arranged between each alarm limiting switch and the alarm. The alarm limiting switches, the button switches and the alarm are connected in series through wires. The alarm limiting switches are connected with an alarm indicator lamp in series through wires. According to the scheme, the belt-breakage-prevention monitoring device is simple in structure, the defects that manual point inspection is hard due to the facts that the number of point inspection portions of an existing through shaft is large, the temperature of a point inspection field is high, and the steam concentration of the point inspection field is large can be overcome, automatic point inspection on the through shaft can be achieved, inspection efficiency is high, and safety and reliability of the device can be improved; meanwhile, the production cost can be reduced, and manpower and material resources can be reduced.