The invention provides an automatic early warning fire extinguishing method for preventing a vehicle from spontaneously combusting. The inside of an engine case is provided with a 
central processing unit, a temperature sensor, a gas sensitive sensor, a 
laser probe, a photoelectric 
smoke sensor, a 
direct current over-current protector, a power 
relay, an oil circuit switch and a 
fire extinguisher. The 
central processing unit is connected with the temperature sensor, the gas sensitive sensor, the 
laser probe, the photoelectric 
smoke sensor, the 
direct current over-current protector, the power 
relay, the oil circuit switch and the 
fire extinguisher through a data wire to form a 
detection early warning fire extinguishing 
system; the outside of an 
oil supply pipeline which is connected with an engine is covered with a transparent plastic 
pipe; an 
oil absorption discoloration 
flame retardant material is filled between the 
oil supply pipeline and the transparent plastic pie to form an 
oil supply pipeline protection structure; and a 
brake oil tank and an engine 
oil tank which are arranged at the periphery of the engine are isolated through a 
flame retardant plate. The automatic early warning fire extinguishing method has the advantages that: the design is scientific and rational; the method gives priority to preventing the pipeline from oil leakage and 
short circuit, and is supplemented by the passive fire extinguishing; and even though the 
spontaneous combustion is caused by the fire of the circuit after the oil leaks, the 
central processing unit can 
cut off the power 
relay and the oil circuit switch as soon as possible, so the loss of the 
spontaneous combustion is minimized.