The invention discloses an automatic protection device of anti-explosive diesel engine. The automatic protection device comprises an infrared temperature measurement device, a water coolant temperature sensor, a water coolant level sensor, an air exhaust temperature sensor, an engine oil pressure sensor, a combustible gas detector, an electronic control unit (ECU), a fuel oil shutoff valve and an automatic fire extinguishing device, wherein the infrared temperature measurement device, the water coolant temperature sensor, the water coolant level sensor, the air exhaust temperature sensor, the engine oil pressure sensor and the combustible gas detector are connected with the ECU through a bus. By the automatic protection device, the surface temperature, the air exhaust temperature, the water coolant temperature and level, the engine oil pressure, and the combustible gas content in an environment can be monitored in real time; and when the monitoring parameter exceeds a limit value, an alarm can be automatically sounded, and protective measures can be taken; and therefore, accidents can be prevented.