A fuel oil provision-vaporization-pressure regulation-full premixed combustion system includes an air pump, a fuel tank, a vaporizing chamber, a preheater, a premix nozzle, an ignition device, a full premixed combustor and an intake guiding device. The air pump communicates with an air inlet of the fuel tank through a first conduit. The fuel tank is provided with a fuel inlet and a fuel outlet pipe. The fuel outlet pipe communicates with a fuel inlet of the vaporizing chamber through a second conduit. The vaporizing chamber is provided with the preheater. A fuel outlet of the vaporizing chamber is in communication with an air inlet of the premix nozzle through a third conduit. An air outlet of the premix nozzle opens to the intake guiding device. An outlet of the intake guiding device communicates with the full premixed combustor. The full premixed combustor is provided with the ignition device.